This one's kind of funny but kind of handy, too.
Imodium, the anti-diarrheal folks who help keep you from spilling your guts (ha ha), present this online bathroom finder. It's pretty simple. Punch in a zip code or city and you'll get a map of public bathrooms in the area. I've had a couple of travel experiences where this really would have helped.
- Stephen Carter-Novotni