Digital BW, The Print

I am new to the digital photo domain. I have a canon g5, a canon i960 
printer for color, and just purchased a c86 for b&w.

I want to learn photoshop, but I am not running XP (and the computer 
that I have will not upgrade easily to xp) which rules out the 
current version of photoshop.

I was hoping to be able to pick up a used version of 7.0 to keep the 
cost down.

Thanks again for your help.