Yeah it's not really all that helpful to download something off the internet. The best way to do it is to borrow cds from someone and get a key generator that will make that xxxx-xxxxx-xxxxx-xxxx-xxx a number. I don't know if you can upgrade from a faked one though. I just have PS CS2, my mom got it for work - illustration - and it came with a family pack. I really love CS3 and CS4, they are like sex.
If you've been working in GIMP, PS is more like that tahn PSP, but I know some people that work exclusively in PSP. you just get to learn the program, you know?