Hey everyone. Sorry for not posting anything in so long, but I've been really busy!
Dwayne from Leftfield Studios might chime in here (I hope!), but I found some free stop-mo software today:
Stop Motion Animator
EDIT: Here's one more. FrameByFrame for Mac
Did anyone else animate Star Wars figures with a Super8 (film) camera when they were a kid? I wish I had a copy of those films. They must have been hilariously bad.
By the way, Dwayne, I love the Leftfield Studios stuff. Great fun! Well done.
Here's a cut-out/vector animation program that I use from time to time in my professional work:
Anime Studio Pro
It's not free but it's really useful sometimes. The intro of my demo reel was animated in it. I also like to draw in it. It renders the best vector lines from a tablet of any program I've used. I've also used it for compositing Maya output with flat elements. Another use is quick mock ups of future 3D characters.
Have fun and keep animating!