I admire the work these folks put in to stop motion. That must take a huge amount of patience and persistence to complete.
I do wish I had the time and mostly the stamina to do things like this, I think its neat. I would think there is free software out there that could make it easier. I also imagine it would be helpful to have a camera that has a remote control so when you snap a picture it wouldn't slightly move the camera and having an odd effect to the stop motion.