From time to time, I get asked how I do these things. The short answer is “each one is different” but a quick and dirty animangle doesn’t take long and isn’t overly tricky. So, here’s a pretty crap animangle (by my exacting standards  – it’s pretty low resolution compared to my usual stuff) to start with. The Finchihuahua:

and here is a 42 second youtube thingymabob sort of showing how it was made while not actually telling you a damned thing about how it was made:

[tube]http://www.youtube.com/watch?v=hD9Ne7CsnmY[/tube]