The Step-by-Step Guide: Demonstrate NAP 802.1X Enforcement in a Test Lab explains exactly how to set NAP up in a lab to measure compliance (and optionally restrict network access) of clients accessing the network by network switches capable of port based authentication including many enterprise wireless access points and CISCO's Network Admission Control.

If you haven't come across Network Access Protection then I recommend reading my earlier post Where can I find out more about Network Access Protection?