If you are looking for an alternative to Prism for building Composite Silverlight and WPF Applications or just want to look at other solutions, you may want to check out Caliburn which was just released as 1.0.
Caliburn helps you build Silverlight and WPF Applications by extending the functionality in the base tecnology:
- Extends databinding to methods, making MVVM architectures simple and intuitive.
- Adds pre/post execution filters and rescues to MVVM actions.
- Simplifies asynchronous programming through a powerful implementation of Coroutines.
- Provides base classes supporting common UI roles such as Screen Activator, Screen Conductor, Screen Collection and Application Controller.
- Encourages a convention over configuration approach to architecting solutions.
- Supports TDD by providing a powerful databinding validation framework for WPF.
- Enables use of the same API for WPF and Silverlight architectures
You can download Caliburn 1.0 here.
You can also find an updated version of Prism 2.1 to support Silverlight 3 recently released.