In the most recent email from Rivendell Bikes (I get emails from them maybe monthly), there was a reference to and link to this Bike Index, which advertises itself on its main page as, "the most widely used bicycle registration service in the world. We strive to be the best resource in the fight against bicycle theft."
They seem eager and dedicated, and the price is right. Logos on the site suggest that some police forces use 'em (Seattle, St Louis, San Francisco). I'm taken enough with 'em that I'm going to sign up after I get pictures of the Yellow Maserati and the Krakow Monster, and The Excellent Wife (TEW)'s bikes.
Check 'em out.
Edit Aug 19: I added all four of our bikes today.