I used to know some wonderful tutorial sites for CS. Sadly, I think they no longer exist. GIMP is the freeware that was developed on Pshop principles, so they are very similar. But what is it that you need to know in order to start?
A lot of the useful stuff is sort of hidden and buried in menus if you haven't ever used it before to know where to find it. Such is the problem when it's a program with SO MANY FEATURES. Even the people who work on it claim that they don't know where everything is.
...I *LOVE* the icon you used for this post though! XD It looks amazing. ♥