Here are the official Zombies? images:

Standard banner

Inline banner

Leaderboard banner

Skyscraper banner

Niftly little button

(NEW!)
If you plan on using any of these, I'd appreciate if you'd save a copy of the banner on your web site. And I'd appreciate no modification of the banner.

If you need another format or whatever else, just ask. I'm here. I listen. Or read.