It seems Adobe has put up the entirety of Creative Suit 2 for free. Sure it's a little outdated, but if you absolutely need to get photoshop without paying for it, this is the way to go.
I've wondered this for quite a while, does Gimp 2.0 allow you to adjust brush sizes? So far I haven't been able to figure out or find out if you could adjust the brush sizes in Gimp.