Windows Server 2008 User Account Controls Video
As you are all aware one of the key changes that was introduced with Windows Vista is the use of User account Controls. These controls segment the user access token, and then manage access to local resources based on the standard user portion of the token. When elevated access is necessary User account control kicks in and we get one of a couple of 
different behaviors. We might get prompted for a password, we might get an administrative approval request. We might see nothing at all.
This feature will be included in Windows Server 2008. It is a great local security tool and rightly deserves to be included in the server family.
There are some recurring questions that I notice with regards to UAC.
Q: How do I turn off UAC?
A: It can be done; however, I would not recommend it. The base security that UAC provides far outweighs its annoying pop ups. In most cases what we really want to do is get rid of the pop ups. To get rid of the pop ups you can change their default behavior.
Q: How do I control the default behavior of the UAC prompts?
A; Watch this 10 minute video segment and I will show you where to go to change the behavior of the pop ups and some other basic stuff about UAC.
2 months ago I recorded a Webcast with intimate details, discussion, and demonstrations of UAC. It is more than an hours worth of good information about the theory and practical application behind UAC. This is a great primer to get you familiar with UAC.