New York City Department of City Planning website has good bike maps for download.
Download Manhattan, Bronx, and northern Queens bike map.
Download Brooklyn, southern Queens, and Staten Island bike map.

Community

Discuss biking in New York City at Wired New York Forum

Bicycle Resources

• New York City Bicycle Network Development
  Information regarding bikeways and greenways throughout the City of New York
• Transportation Alternatives NYC-area non-profit citizens group working for better bicycling, walking and public transit.

Pictures

Bike path – Hudson River Park.