I spent the last couple of days at VSLive! Boston. I gave a talk on Wednesday on "Writing Secure Plug-Ins Applications in .NET". You can pick up the slides here. I had some problems with my VPC image the night before my talk, so I will need to finish (i.e. rewrite) some of my demos and post them this weekend.
The talk went very well with many great questions and interest in the topic. I like the new support in .NET 2.0 for creating and securing AppDomains through the AppDomainManager and the HostSecurityManager. Unfortunately, some of the demo code I had a few months ago was broken when run on the April Beta 2 (mostly renaming of Flags to Options in some cases). In my talk, I briefly touched on some of the newest features related to CLR Hosting, but I want to personally dig into this more, especially best practices for implementing policies through the HSM.