(Sorry if you received two copies of this post…I missed named the title and that caused the URI to change).
Not sure how I missed this, but in late December, the PnP team shipped their Inversion of Control (IoC) container for Silverlight called the Unity Application Block. This is a port of the Unity Application Block that has been available for .NET for some time. For more information on IoC containers (and the Dependency Injection pattern), see Martin Fowler’s article here.
To compliment this, I know the team is also working on a port of their Composite WPF Application Guidance (which optionally uses the Unity Application Block) for composing large applications from smaller pieces. This guidance is a great way to build large Silverlight or WPF applications. They are working on the Silverlight version of this and hopefully it will be released soon.