If you haven't already, check out Bike Index, a free, non-profit, online bike registration service, that can help aid in returning stolen bikes back to their rightful owners.

Registering your bike online takes about 2 minutes and is completely free. Include photos, a serial number, and as much detail as you can - if your bike goes missing, you mark it as lost or stolen and the Bike Index community and its partners will be notified.