Over at The Simpson Movie website you can create your own Simpson's avatar by following a link at the top of the page. You can see my handy work to your left.
Even more interesting is the Simpsonize Me site where you can upload a photo of yourself and have it generate your Simpsons character likeness. I've been trying for awhile now to get it to work on one of my photos but the site is being hammered by traffic so your mileage may vary.
My ultimate goal is a family portrait of Kate, Anna and I.