Saw a mention of this in the latest MSDN Magazine, you can download Reflector.SQL2005Browser and install it as an add-in for the well know Reflector tool (both are free). Point it at a server, pick a database, and you can browse through the deployed CLR objects. From there you can pick a function and disassemble to the code of your choice. Defaults to C#, but does VB.Net as well. Probably not something we DBA's will use every day, but nice to have available when you do need it.
I'm Andy Warren, currently a SQL Server trainer with End to End Training. Over the past few years I've been a developer, DBA, and IT Director. I was one of the original founders of SQLServerCentral.com and helped grow that community from zero to about 300k members before deciding to move on to other ventures.