The MS Developer and Platform Evangelism team has produced a series of AzMan developer Web Casts hosted by Keith Brown, check out the first of the four part series:
Watch Donovan’s blog for news on the rest of the series; http://blogs.msdn.com/donovanf/
Here’s some additional video resources I’ve been remiss in not listing.
ADFS/AzMan .Net Show
A discussion on ADFS and Authorization Manager
ISV Chalk Talk – Windows Authorization Manager
An introductory interview about AzMan.