Here is a cool tutorial I came across on Creative Cow.Net. It uses the principles of rotoscoping (a technique where animators trace live action movement, frame by frame, for use in animated cartoons~source:Wikipedia).Aharon Rabinowitz's tutorials are great on Creative Cow and they are easy to follow and well thought out. I recommend looking through all his tutorials on Creative Cow when you have the time. The one draw back is that these tutorials are software specific and even version (of software) specific. This tutorial focuses on using Adobe After Effects 7 and Adobe Illustrator. Here's the link, it's a three parter, so grab your cup of coffee and enjoy!