Well I learned by fiddling around in PSP & copying other people & being in groups (MSN then but now they're forums or Yahoo groups) anyway just picking up things here & there & lots of practice which was fun cos I loved it. And following tutorials. You learn a lot by doing that. But yeah, nowadays there are classes. So google PSP class or beginner psp - stuff like that ... I don't know any personally to recommend sorry.
You do need PSP (Paint Shop Pro) which still has a free trial download I believe from Corel. I bought my own halfway thru my free trial, I knew that I loved it.
Good luck - anyone can learn!