As a follow up to my Implementing IDisposable and the Dispose pattern article, I have posted a new one on SafeHandles and Constrained Execution Regions (CERs).
This article explains the new SafeHandle class, introduced in .NET 2.0, and how to use it. I also cover CERs and how they are used.
[Update, 22-Jan-2008: Updated the article link for Code Project.]