Check out VeloNews TV. They’ve got four pretty good technique videos that display dismounts, mounts, lifting/shouldering, and barriers. The advice is solid and the production is fairly goo though I’d have liked to have seen more iterations of each skill.
The two quibbles I have regard shouldering the bike. One of the best pieces of advice I’ve been given for shouldering with arm wrapped around the down tube is to flex your bicep. This accomplishes three things: 1) positions the bike properly fore and aft so that your seat doesn’t bop you in the head, 2) steadies the bike so it isn’t flopping around, and 3) takes much of the load off of your shoulder. I got this advice from Erik Tonkin during one of the Sellwood Cycle Repair clinics. The second quibble is the advice about grabbing the down tube during the dismount for shouldering. I see this as optional. Some racers find grabbing the down tube less stable especially over rough terrain.
Still, a nice resource. Thanks to crossniacs.com for the heads-up.