Hey, just found a new free program that you may want to check out. It's called Inkscape and it can be downloaded here: http://www.inkscape.org/download.php Try it out and post your reactions here, if you'd like.
Also - I'm not sure that I've ever recommended Gimp but you can download that here: http://www.gimp.org/downloads/ If you don't have a license for Photoshop, you may want to check this one out before buying it. This program is a little more difficult to use at first, but I find that it does everything I would use Photoshop for, and it is free.
Prior to checking out either of these, I have a question. Would either of them allow me to open an Illustrator (*.ai) file? I can't do this with Paint Shop Pro (my current graphics program), but would like to be able to do so. *.eps files work in Paint Shop, but not *.ai.
If neither of these can do so, are there any other recommendations for an open source program that can?