Dude, check out this tutorial. It worked for me when I didn't know the basics. Anyway, I think Photoshop CS2 would be a better choice, since most custom brushes are compatible with it. I use Total Deviance brushes, they rock.
ok so i got the CS2 started workin on one and its a lor harder than i thought.. even with that tutorial i got the render but it came with a background and i cant seem to get rid of, its started 2 gove me a headache now, im going to leave it for a while.