As far as Photoshop goes, the question is where to begin? I have used Photoshop since 1992 on an old Mac computer. I have evolved with the program and now have CS. I haven't upgraded to CS3 (CS4 is coming out real soon) because I have been comfortable with where I am. I now am going to upgrade because I want to begin shooting in RAW and use Lightroom 2. Photoshop is an awesome, powerful program. I still learn new things almost daily. The best advise I can give is to open it up and play with it. Use the tutorials available on youtube,
MCP,
Unsharpmasked and I'm certain there are many others. There are so many, actually countless possibilities with Photoshop, learn it and use it.