To celebrate the release of their Plants vs Zombies game, Pop Cap have also released the Zombatar where you can create your own custom zombiefied avatar.
PopCap Games - Plants vs. Zombies
The final image will need resizing to 100x100 to be accepted on these forums.
So have fun and do your worst! Yarrr!
If your interested in the game, further information can be gained by visiting: Plants vs Zombies Official Site - PopCap Games - Free Download Games