What bikes will be used by the competitors in the Mountain Bike Olympics? I'm just curious to know what bike models and setups will be used by the competitors? Is there any data out there on the web?
There was a test event on the Hadleigh Farm Mountain Bike course which will be used for the 2012 Olympics. There are various photos and videos of the event which show the bikes being ridden:

Videos on YouTube

Photos from The Guardian

Photos from Cait Elliott

From looking at these:


Everyone seemed to be using carbon fibre frames
Most riders used a hard-tailed bike, although some had full suspension
There was a mix of wheel sizes (I assume 26 and 29 inch)


You can make out manufacturers names on many of the bikes and in some cases on individual components if you're particularly interested in those.

Edit - a few things I picked up from the commentary on the 2 races:


In the men's race there were 3 different sizes of wheel in use - 26, 27.5 and 29 inches.
Most of the riders opted for a single chainring, with the rest using 2.
Suspension travel was around 100mm with the suspension set hard.
Tyre choice was small lugs to give better grip on the rocky sections.
At least one rider was using a "lefty" fork.
Some riders were carrying gas canisters to deal with punctures.
Bike weight was around 19 pounds (8.6 kg).