Here are some links I used to prepare for my presentation on Policy-Based Management in SQL Server 2008. SQL Books Online is also a great source of information.
SQL Server 2008 Policy Based Management Interview
Using Policy-Based Management in SQL Server 2008
Use Policy Based Management Features of SQL Server 2008 to Manage SQL Servers
SQL Server Policy-Based Management
This blog is dedicated to Policy-Based Management introduced in SQL Server 2008
ExecuteWQL() in Policy Based Management
Microsoft SQL Server 2008 Feature Pack, October 2008