Place the document on a desk. Then, step onto a chair. Try to be almost directly on top of the document, without causing a shadow. With appropriate lighting, this shouldn't be a problem. Then, take a few shots. Instead of just taking one, I've found that taken at least four shots will ensure that at least one of them will be properly in focus.
Once you've taken a few photos, it's time to resize them to a decent size using Adobe Photoshop, Elements, or any other image editing software. When you're in that program, try to resize the image to something like 1,000×1,500 pixels. I've found that this makes the 'scanned document' manageable enough so that anyone can receive it in their email.
It's important to be properly aligned with the document, otherwise you'll end up with slightly skewed shots, which could be a problem. You could also use some kind of brackets or holding arms in order to fasten the camera in place while you take a photos. Most tripods won't tip down enough for this to work, but if you place the document on an easel, it would be feasible to find the right angle for alignment.