CNET (which seems to be the answer to a lot of things) does reviews on these things. But a lot of it depends on what she wants to do. This will decide some of it; such as megapixels/resolution, or if zoom is required.

On the backside, you have to look at the media it uses to store the picture. There are basically three types;
- those which store it in unremoveable memory - you will download and erase the camera
- those that use removeable (either smart card, flash card, or stick memory). This is nice because you can have an endless supply of pictures by changing the media. You will have to look at how you get the info into the PC (like a USB or through a media reader).
- those that store on a floppy and now a CD-RW. Nice because of the endless supply, plus the ease of transfer to a PC/Mac.

Here are a couple of articles to get you going:

http://www.photo.net/photo/digital/choosing
http://www.shortcourses.com/choosing/contents.htm

and then when you are ready, look on CNET to get some reviews.