I started porting some code from the Compact Framework over to Silverlight for Windows Phone.
I have created a project on codeplex: http://wp7.codeplex.com/. The solution so far contains an IoC with support for implicit dependency injection - in fact this is a port from the Compact Container on the CF. It also contains a port of the Common Service Locator for the desktop by the p&p team at Microsoft.
The project is designed to be a work in progress and I'll add stuff to it if I think it might be useful to others.
I do plan over the next couple of days to add an event aggregator to the solution that will integrate with the container nicely to promote nice loosely coupled multicast event model in your Silverlight applications.
I am also working on an API that allows communication with the Microsoft Azure Service Bus - much like you get on the desktop. I will checkin as soon as it is available.
The current solution that is checked in is designed to be used with the latest release of Windows Phone developer tools beta.