Bike Around Bend:

http://www.bikearoundbend.com

Central Oregon Trail Alliance:

http://cotamtb.com

Deschutes County Bike Guide:

http://www.visitbend.com/Deschutes-County-Bike-Guide.pdf

Bike Central Oregon:

http://bikecentraloregon.org

Find a Ride:

http://rideoregonride.com/rides/