Macromedia Flash
Flash can be regarded as the Photoshop of animation. It is very very costly, but it is worth it for intermediate and professional web designers. Although animations made in flash require a special plug-in to be viewed, the majority of people have this plug-in.
The animations inside of Macromedia Flash are done frame by frame, and it takes a little while to get used to it, but it's definately worth it in the end.
Many of my animations on this site are done in Flash
