Make Your Own Animated Movies with Pencil
Pencil is not just a 2D drawing software. It’s also an animation tool using the transitional way, i.e. drawing frame by frame and playing them in sequence. In the end, Pencil can export your drawings or animations to SWF flash, QuickTime MOV or a sequence of PNG images.
As mentioned by the author, this software isn’t intended to replace the commercial flash tools but a program that let anyone to make amateur 2D animation. Pencil is a cross-platform software.
I have used DrawSWF, a Java-based drawing program, to make flash animation. However, the animation is generated from the sequence of your sketching, not really the movement of an object. It is fun to play with. Unfortunately the project hasn’t had any progress for a while, and the software only supports Java Runtime Environment 1.4 & 1.5.
(via Digital Inspiration)