I showed this stuff at the Ready Tour we did around Australia late last year. A few people have asked me for more details so here they are.
The scenarios Im showing in the two screencasts below are about IPSEC enforcement.The good thing about IPSEC is its based on machine to machine authentication. This allows you put in place a layered defense internal network that implements the authenticating firewall in Vista. What does that mean? Well imagine that you couldnt connect to an service or even port scan what was on the service till your machine authenticated to it. Add into that mix that in order to get the certificate to establish the IPSEC communication your machine must pass a compliance audit of ensuring that it has an update to date antivirus application, a firewall running and automatic updates running and up to date aswell. Thats essentially what NAP is all about!
So anyhow - take a look at the two screencasts below - any questions feel free to put comments on this post!
Video: Network Access Protection for the Server
Video: Network Access Protection from the client perspective