The Right Ride has several sites available to help cyclists track safe routes and dangerous spots around various cities in the U.S.. It’s a nice Google Maps mash-up allowing visitors to click on individual pins on the map for more information about the routes and hazards which registered users have added. Registration is free if you’d like to help map out routes in the following cities:
Boston has the most information on-line. Looks like they’re also working on New York and are open to adding cities.
Tip of the helmet to Eric at KCBike.info (who got them to add Kansas City).