(Graeme [Strange] suggested I catch up with the Readify blogs, so I've been reading recent posts.)
Note that the .NET Framework already includes a complete implementation of a dependency injection framework in the System.ComponentModel namespace.
It allows you to inject components which implement an interface into a service locator at runtime. Service consumers are then coded to search for the components they want via the public interface. All the plumbing handling service registration, etc, is handled in the .NET Framework.
The following post by Daniel Cazzulino has more information and gives some examples.
Mitch Denny has also previously posted on this.