Below is a link to a white paper I wrote on Policy Based Management.  It serves as a guide to not only explain the technology but also walk you through setting it up and designing some policies.  You can expect to learn the following:

• How to enable PBM
• How to create a policy
• The different ways to evaluate a policy
• Where to find and import Microsoft best practice policies
• How to setup alerts to be notified of policy violations
• A list of common use cases

Policy Based Management White Paper