For those of you who haven't played around with it, try out google picasa (free photo editing software). I have photoshop elements but have been a bit intimidated to really delve in. Picasa has some quick/fun effects (and yes, gives me another opportunity to post a pick of baldsmith!)
Gimp is the real deal. But not very friendly for the beginner. Picassa only works so-so on linux. (But then, I don't have a good version of gimp on mac either...)