I have used Snapfish and it seems to be ok - make sure you do a full color correction with a calibrated monitor, though, otherwise pictures could end up significantly darker/lighter than expected. Even if you do a full color adjustment, sometimes colors end up a little "flatter" than expected.

Pricier but better and with a lot more finishing options is mpix.com, which is what the pros use. The colors WILL come out correctly if you use Mpix, but the prices are prettymuch double those of snapfish.

I have found realmemories.com to be a great source for photo framing. You can upload your digital photo, then choose a mat and frame, and they send you the framed and matted photo in about two weeks. It's not super cheap (about $30-$50 dollars for the finished product, depending on the frame you choose) but it is pretty high quality.

Try rrcolor.com
They have always done a wonderfull job on my
prints.... of any size.

IMO, this sort of large format printing is better done in local print shop, so that you can check the color calibration in person. If you are to order really large size print, it's worth doing a small proof first.

Having said that, if you really want to use an online service. I recommend two:

Photowork San Francisco. I have good experience with both their online services and visiting in person. I had them print a 40" by 40" canvas from a medium format negative. It looks great.

Mpix is another online service. I use them to print small photo books. They are quite good. But I haven't tried doing large print with them.

IMO, large print is best done in local print shop. That way, you could check color calibration in person. For really large print, it's better to have print a small proof first. Having said that, I have 2 online services to recommend:

Photowork is based in San Francisco. I have very good experience with both their online services and visiting in person. I had them print a 40" by 40" canvas from 120 film. It looks great.

Mpix is another online service. I use them to print small photo books, which are quite good. I haven't tried large print with them though.

UPrinting.com. I have done several extremely large photo prints on canvas (think 4' x 6') and they have been very accomodating. They actually have a customer service rep call you about your order. They also do prints on paper and such.

You could look into getting a wide format printer and printing them yourself. Printers have come a long way in the past ten years and you can get some stunning prints from the inkjets, even in black & white. I have an Epson R1800, which is a few years old and sells on Amazon for $499. It prints up to 13" x 44" and the I love the quality.

Most people don't think about these because they think the cost of ink will be too high to maintain but, I buy off-brand ink on eBay for a ridiculously low price. Quality paper makes a big difference though so, that's where I'l get the good stuff.

If it's something that you think you might do often, go to your local Best Buy, etc., and check out the latest offerings. The usually have sample prints to see.

My wedding photographer suggested mpix.com (lustre paper)... I haven't gotten any prints yet though. It's on my to do list!

I recently made a cool-looking photo wall for a friend's travel photography using CollageWall. See the result here: http://collagewall.com/examples/344. I don't know an easier way to get your digital photos on the wall.

I've used Photoworks.com (the Seattle company) for some large format wall prints and they turned out great. I was a little nervous after using snapfish previously for smaller prints (that didn't turn out that great). Just make sure you submit really high-quality images.

my husband's a professional photog so we print TONS.

we've had excellent results with mpix.com--and they have a wide range of papers to choose from. if you're thinking of going super large (the largest we've ordered is a 20x30 and that can be a touch pricey), i'd highly recommend ordering test 4x6 prints in each of the papers you're interested in to confirm your pic's colors (sometimes what you see on your monitor is not quite what you get) and paper sheen. the different papers really do enhance pictures in different ways--i kinda dig the metallic...

we've been using precision-camera.com more recently. although they don't offer such a wide range of papers, they're local to us (they ship also) and they offer a custom touch with processing...

how fun and best of luck!

I would recommend West Coast Imaging at www.westcoastimaging.com . Their work is extremely professional and they offer great specials every month. They do my gallery work and I've never been disappointed. Try SuperGloss paper; gorgeous stuff and they have a special on it right now.

I swear by MPIX.com

Seriously.

MPIX.com

I do all my prints through there, my books, albums, etc (I do wedding photography.) I have never been unhappy with their work, it's fabulous every time. I LOVE the metallic print paper (try it out small though to see if you love it as much as I do). It might not be what you're looking for, but their regular prints are just as great. And fast turn around too.

Ooh, and they have Standouts, so your print is ready to hang and has a great finish to it without needing a frame. They also do gallery wraps, but it depends on how much you want to spend. See your options here: http://www.mpix.com/Mounting.aspx

I've used AdoramaPix out of NYC forever. They're really reasonable ($1.84 for an 8x10) and they print a ton of sizes on all kinds of paper.

They're particularly good (and well priced) for the much bigger print sizes... all the way up to 24"x36"!

http://www.adorama.com

They've always done a fantastic job for me.

Try Sam's Club. They use Epson printers for the big prints. Amazing quality, an 11x14 print is $3, 20x30 is $12 and can be done in an hour.

I second the vote for Adorama, although I have heard really good things about mpix

www.largeformatposters.com I've used them. Great work; inexpensive; they'll send proofs if you would like them!

I've used mpix.com several times and have been incredibly happy with their results. I do all the color calibration at home, so I didn't need them to do any tweaking, but they will do that for you if you want.

prices are good, and their packaging is sturdy enough that I have never gotten as much as a bend in my prints.

If you want prints of 8x10, 11x14, 16x20 or bigger, I recommend that you find a professional color lab in your local area. They can be found in your phone book under "photographic developing and printing". Whether the shots were taken in digital or film, a professional lab should be able to provide you with excellent enlargements.

Keep in mind that the lab's ability to make large print enlargements from digital files will hinge on the image's file size. Meaning that large enlargements of 11x14, 16x20, or larger cannot be reproduced from smaller file sizes without noticeable image problems.

@ Jeff Southard

Cool collage! The period at the end of your link above is messing it up, fyi :-)

@mjr
Thanks. Here's the link again:
http://collagewall.com/examples/344

adorama for the win.

I sent them a test first with the same photo and tried al of their papers, and then went from there. you can go up to 24x36 in some papers.

benefits: true digital format instead of a 4x6 that is cropped to fit, or a 4x6 and you choose how they crop it, optional white borders, cutom imprinting on the back.

GREAT prices. They will often run specials too. So if you know you are going to print a lot of one size you can prebuy a set, and then use them as you want at the cheaper price.

Plus, they have a tech as they print, that reviews things as they come out. You can choose, to leave the photos alone or have them adjust as needed.

$5 flat rate for shipping. bad for small orders, great for huge ones.

haven't tried mpix, but will check it out now.

I'm a photographer, and I've used Color Inc. many times for standard print sizes ranging from 8x10 to 16x20. Their prices are great, their shipping is fast (and free over $15!), and I'm confident my prints will arrive packaged securely. They're my first stop for any printing needs.

http://www.colorincprolab.com/

i've been pleased with my prints from qoop, which partners with flickr.

Try professional prints from http://www.beta.kodakgallery.com which is a new site for professional printing with some really cool paper options, I would check out the metallic paper if you have cool scenic photos, the ones I got were awesome.
They use the same lab to produce the prints as mpix so the prints are color corrected and come about 2 days after you order them. Right now there's a sale on 8x10 prints and free shipping, but they also have larger sizes (11x14 up to 20x30).

I've used Adorama since my wedding photographer, who is also a photojournalist, recommended them. They are great.

I have had several large size prints made at Kodak from a rather inexpensive digital Kodak camera. I download the pics onto my computer then order them directly in a few easy steps.
The finished product is real great quality and the price is great too!

Thanks everyone for your suggestions!!

if you are in European Union try www.printao.com

I use Canvas on Demand all the time. The quality is really nice and the corners look good.
Canvas print coupons from http://www.printinator.com They have lots of canvas print coupons! You should tried them ;-)