I frequently blog about Code Styles & Standards. One of the references that I use a lot when trying to justify a change to a companies existing standard (or simply putting a standard in place) is the Framework Design Guidelines
by Krzysztof Cwalina and Brad Abrams. Both of them today officially announced that they are working on the Second Edition, which will cover the .NET Framework v3.0 and v3.5 releases, including LINQ and the other language advances.
They are both looking for feedback on what topics should be added, what changes should be made (topics clarified), and what new annotations should be added.
The new edition should be out by the end of 2008. I can't wait, but if you don't already have the first edition go ahead and pick up a copy. It's definitely worth getting.