i found an awsome animation program! but its only 4 macs. it's has a free trial. If you want a sig like mine the download this! http://www.versiontracker.com/dyn/moreinfo/macosx/13887 its called iDraw! and it's easy to use!
Macs RULE! OK, my iMac G4 has become a little slow through the years. But it's still much faster than PCs with similar hardware...
Just to build animated GIFs I recommend this program, which is completely freeware but has some more possibilities concerning GIFs as far as I can see, for example you can change the time, a frame is shown for each frame seperated: GifBuilder