The options that have been mentioned all sound really good. If you want to persue photshop then look and see if you can get a previous version such as cs, cs2, or cs3 as they have not changed the core of the program significantly, mostly just bells and whistles, maybe interface changes. Just be sure to get a legal copy if you want to upgrade later.
For others looking into this thread... i just got CS4 and like the new options but have had to update the dirver for my graphics card as well as my wacom. I have been having some speed issues. While the new interfaces and changes are cool... i am frustrated anyone else having that problem?
Also dont bother with getting PS extended.
Elements will more than likely be all you need.
A great source to learn about how to use photoshop is Learning @ Your Own PaceŽ - lynda.com
I do the monthly subscription and find invaluable. After using PS for nearly 10 years now I learned more about the depth of that program in 2 weeks using lyndas video tutorials than all of the ten years previeously.