I had a great interview with Nate Kohari, the creator of the Ninject dependency injection framework.  The interview was for InfoQ and of course, I think it's worth a read.

Ninject runs on a variety of .NET platforms:

• .NET Framework 2.0, 3.0 and 3.5
• .NET Compact Framework 2.0 and 3.5 (Ninject.Core and Ninject.Conditions)
• Silverlight 2.0 beta 2 (Ninject.Core, Ninject.Conditions, and all shipping extensions)

There are a few competing dependency injection frameworks available but this on seems to have a lot to offer and a strong following of developers using it.  Nate even has some swag, in case you might be looking for a shirt to help support his project.

You can read the interview on the InfoQ web site.