BINGO!!!!!!!!
My system originally had 1 GB of RAM and I would say it ran Photoshop CS2 alright. Some of the filters took a little longer than I liked so I upgraded to 2 GB. I would say 1 GB is the absolute minimum regardless of what the box says (for CS2 anyway).
I have taken 4 Photoshop classes the past couple years and it's a pretty intimidating program at first. Stick with it and you can get the basics down fairly quick and you'll find the layout is actually quite user friendly. Now to master it, that will take years and years. Even my profs that taught the classes said they were not "masters" with the program. It's extensive!!!!!
Depending on what you want to do, you might be better off with a lesser program.