Some links to good MTB sites:
General interest/manufacturer sites:
IMBA
Cambria Bike Outfitters
Bike-Swap.Com
Bikescape
Mountain Bike Review
Velonews
Shimano
Universal Cycles
Local/New Mexico links
The Tuffriders MTB Club is a great group. Visit their site for the latest trail/trail work info, and schedule of events.
LA's own DOME Bike Shop Hey, Cambria may be cheap, but you should support Scottie. His prices are competitive with anything you'll find in New Mexico, and he's a great guy.
"Trailmonkey" has Pawel S's old LA trail guide on it. This is a good guide to around 10 of the trails mentioned here, but I hesitate to recommend it, as it utilizes (presumably illegal) copyrighted material from "LA Hiking Trails and Jeep Roads" by Kron.
Land of Oz bikes
A trail guide courtesy of Land of Oz. Has a couple nice maps.
Southern NM Mountain Biking. I've heard there's lots of awful sand. But maybe if you look here you can find the trails that don't suffer from this affliction.
NM Mountain Bike Racing Schedule. Interested in racing? There are all of 6 or so events in NM... go to Colorado, fool. Of course, the competition is a little stiffer, I'm told...
"Rick's Bike Shop? Never heard of it, but here's a link.
Sandia Peak Website has race schedules, and info on the summer MTB possibilities at the resort. Riding the lifts for a day is pretty fun, even if they are godawful slow.