You need the right type of photoshop.It all depends on the program,but photoshop uses vector art in it,and I think Zophia said she draws in Photoshop essentials or something like that.It costs a ton of cash though,so unless you plan on making a full hobby/job out of art then I would suggest that you just stick to GIMP.
Photoshop Elements. 6.0, to be exact, and actually Elements aren't too expensive, compared to the quality of the program. But it is an expense. There's always the free trial, though, so give it a try if you're considering it. GIMP is a decently good program, but I personally hate to use it for anything other than animation. It just doesn't have the same brush quality...
Another free program that can be worth trying out is Krita. It's approximately as good as GIMP.
but photoshop uses vector art in it
I still haven't figured out how to do vectors in Photoshop. The standard settings does raster art.
nywho, I have a question...I was wondering how the 3D tool in PS CS3 are used...how would you import a 3D mesh into PS to work with it?
I have absolutely no experience with any of the CSs, so I am very sorry, but I can't help you out. Google for tutorials?