Bike industry pals::
Seven Cycles - The East Coast Kings of Titanium.
Shimano - Making bike components longer than Campy.
Mavic - Those Frenchies make good rims and wheels too!
Eriksen Cycles - Custom bikes featuring Maverick components
Spot Brand - Great single speeds

Advocacy::
Colorado Mountain Bike Association - Colorado advocacy at it best
International Mountain Bike Association - THE group for off-road cycling advocacy
Boulder Mountain Bike Alliance - Getting things done in Boulder
Bicycle Colorado - One of the best state cycling advocacy groups
Bikes Belong - Keeping bikes a viable part of the U.S. transportation mix
Sierra Buttes Trail Stewardship - These guys know how to keep mountain biking alive
Southern Off-Road Bicycle Association - Keeping mountain biking strong in the South

Media::
MTBR - You can find it all here
TwoSpoke Bike & Cycling Forum - Bicycle forum and reviews for all types of bikes
BIke Magazine - Great mag...fantastic photos & journalism
Dirt Rag - An interesting view of the bike scene
VeloNews - The top bike racing journal

Adventure::
Elk River Touring Center - West Virginia mountain biking heaven
Adventure Cycling Association - Lots of great ride choices

Other great sites::
Oskar Blues Brewery - For after the ride...