CreaToon
CreaToon is a free easy to use animation program. It is different from other programs however, because you don't draw the objects in the program, it is a cutout based animation program. What that means is you make the parts in something like Gimp or Inkscape, and then you import them as png images into CreaToon, and you animate the characters with the body parts you made. You would have to check it out to see what I mean, it's a cool program though. I have Windows 7 64-bit and it runs fine on my computer (accept for the preview window is all black, but that is because of my graphics card, not the OS). It is also supposed to work pretty well in Wine on Linux and Mac.
