I checked out a cool image generator site after getting a "tweet" from someone I follow on Twitter. Check out BeFunky. It allows you to cartoonize, along with many other ways to customize, your photos. Here is an example of one photo, many ways...
My original Photo (George the Squirrel)
George (Scribbler effect)
George (Sunburst effect)
George (Stenciler effect)
George (Patriotic effect)
George (Charcola effect)
George (Cartoonize effect)
These are just examples of what can be done on this site, there are many, many more options. I was thinking you could create your very own avatar, using an actual photo of yourself. I may have to try that.