Antics3d have released v3 of their 3D pre-viz animation software, which now apparently includes a completely free base animation version. I have played with the trial of v2.5 and found it interesting if a little limiting. However, the new version looks promising.
The other application that I discovered today by complete chance is a very similar product called Moviestorm a Java based program that appears to provide much the same functionality as Antics3D. This program is currently in beta (v2), but also provides a range of free content and seems to be fairly useful at the current level of development.
I realise that these aren't 2D animation programs, but worth giving a look if you have any desire for doing 3D Machinima or 3D pre-viz work (and maybe have been intrigued by iClone, but didn't want to outlay the $$$$ to buy all the program and content required to do anything).
Free 3d pre-viz applications
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