Is there a tool to select some code in Visual Studio and have it show the corresponding MSIL?

.NET Reflector

I think that RedGate have bought the IP to this tool now. I'm fairly sure that there is a VS plugin which integrates to it to allow you to run this from vs.

.Net Reflector Plugin
_{(source: mutantdesign.co.uk)}

You could use testdriven.net an awesome unit testing plugin that gives you the ability to right click on any member and view it in reflector.