Any post about websites for kids comes with the de facto statement that we here at Ohdeedoh don't believe that kids should be logging a lot of screen time. But chances are, if you have a preschooler and there's a computer in your home, by now you've started letting him or her start to explore the wonders of the world wide web. Here are a few destinations to consider.
Preschoolers love to learn and are so incredibly curious about the world around them. The internet can enhance this by offering games that make learning fun, and by letting them see people, animals, and things they might otherwise never get a chance to see. In the past couple of years, my now-five-year-old has been really engaged by these sites:
PBS Kids
Okay, goofy confession time: I don't have cable and therefore don't watch television. But I still love the PBS Kids website, as does my son. The games section is excellent, full of tons of educational games – from reading and science to music and healthy eating – that your kids will love, even if they've never watched the original shows.
Starfall
Starfall is a phonics-based learn-to-read site that, despite its somewhat cheesy animation style, is more than compelling enough for my son. More important, it actually works. The site starts with games oriented toward teaching younger preschoolers how to sound out the letters of the alphabet, then works up to progressive reading levels.
How Stuff Works
This site is a must-bookmark for every child going through the perpetual "why?" phase, and for every parent who wants to provide real non-dumbed-down answers. The content on this site isn't 100% kid-appropriate, so this is a site you'll want to navigate with your children, but that's fine. The information contained here will fascinate you as much as it will them, and you may be surprised at the complex concepts your kids are capable of absorbing. The collection of mini-documentary-style short videos is fantastic. (My son and I once spent an afternoon watching every video we could find about magnetism.)
YouTube
You've probably already introduced your little one to the wonders of YouTube, but if you haven't, consider exploring this content-rich resource with them. Again, this site isn't always family-rated, so you'll want to be by their side, or consider creating a video playlist just for them. Some of the videos my husband and I have shown our boy: vintage Sesame Street, Rube Goldberg machines, lots and lots of animal videos, and this crazy animation featuring Ravel's "Bolero".
Flickr
The photo equivalent of YouTube, Flickr lets you expose your kids to so many of the amazing wonders of the world. We do keyword searches based on whatever our current obsession is – spiders, native masks, cats, frogs, slime molds – and then click the "slideshow" option on the search results page. The resulting slideshow is always stunning and inspires us to learn more about the topic.
Do you have any favorite sites for kids? How do you and your preschooler use the internet? Please share in the comments!
(Image: Flickr member Fayes4Art, licensed for use under Creative Commons)

Ercol Bar Stool
You can put a filter on youtube (click on safetymode at the bottom of the screen), but it's not great.
I recommend Kideos (http://www.kideos.com/) instead which has a nice selection of videos for kids - some cartoons, funny animals etc...
National Geographic Kids also has a great site http://kids.nationalgeographic.com/kids/ - my 3 year old daughter loves the wildlife videos.
Thanks for the great suggestions! Always looking for safe/educational places to visit online. It's a good change of pace at times. We also love:
http://www.miffy.com/
Fun games and stories.
Tot LOL is a great site too ... it's videos from all around the web (mostly YouTube) but they've been screened and parent-approved. This way I don't have to worry about my preschooler clicking on the wrong "related video" on YT and getting something unsavory.
http://www.totlol.com/
Thanks for all the great suggestions! My son loves Starfall. Another fun site is the Reading is Fundamental (Leading to Reading) website for preschooler's:
http://www.rif.org/kids/leadingtoreading/en/leadingtoreading.htm
BBC's Cbeebies is a lot like PBS but has totally different games. Both my kids love it, even though my daughter has no idea what the shows are (my son used to watch BBC when we lived over there). We pretty much restrict both kids to PBS, Starfall and Cbeebies. And really, even for my eight year old, that is plenty.
Don't forget about poissonrouge.com! Tons (and I mean LOTS) of simple, interactive games, puzzles, coloring. Even introductions to different languages and art.
I use the site http://www.kneebouncers.com/ for entertainment with my son. He loves pushing the buttons to see what happens.
My litle ones love www.poissonrouge.com :)
My husband recently launched http://www.madeinme.com and I can honestly say that both my kids have already spent many amazing hours playing around in 'The Land of Me' ("A magical learning experience for adventurers ages 2 and up") I'd love you to take a look, I'm sure you're kids will love it too!
www.uptoten.com is a great site.