Hey There!

There most certainly is a map of the bike lanes. Every year the city puts out a free bicycle map. You can find it online at the Department of Transportation's website, here. The maps are usually stocked in your local bike shop and you can also request one through 311.

Be sure to use Ride the City on the Biking Rules website to pick bike routes to your favorite destinations. You can even save routes and share them with friends by clicking the blue "share" button on the Ride the City map view. The "share" button will give you a number of options, from SMS to email to web publishing, pass along great bike route suggestions to others.