Photoshop (Which version is irrelevant, though some of the tutorials might use features only available in CS4 and CS5)
Basic+ knowledge @ Photoshop
A Creative Mind
A Nice Cup of Coffea (to keep you going!) :)
Today I would also like to share a nice 'tool' which could be helpfull.
Deviantart is simply a site where you can share your artwork and comment and see others, the artwork goes from paintings, photography and the list goes on, I advice you to check it out if you don't already know it (which many of you might).