You don't need any fancy software to do a good photoshop; I just use the Microsoft Picture It! that came with my computer, and if you don't have that, Eric has a link to some freeware. For example, I just put together this admittedly lame "Christmas Tree on the RPCP" entry in about five minutes:
For good results, you might want to spend a little more time than I did. It's fun for the whole family!
