I was in the same place you were when i first started. I had no experience and sucked hard at it. I typed in Photoshop Tutorials in google and came up with about a million websites. All of which had something useful. Personally i like starting from scratch and making something out of it with the use of filters, renders, etc and they are everywhere on the net. I bought a book for CS2... and honestly havent used it much. tutorials with step by step instructions are they way to go.
Are you attending school by chance? or know someone who is? I go to UW in WA and I get a student discount from all that software.