I've been searching for animation software myself some time ago, and the best
I've found was Synfig. You will find it in Trisquel repo.
sudo apt-get install synfigstudio
or via Synaptic.
http://www.synfig.org/cms/
I didn't have much time to dive into it (plus I'm not an animator) but while
the software doesn't seem to be necessarily simple, it also doesn't seem too
complicated. They have some helpful materials on the site, incl. a pay $1+
'video training course'. I think that with a few days spent on learning you
could be cracking through it without much problems :) I noticed some
tutorials on *cough* youtube as well.
Hope that helps.
