Automapper, your favorite object mapping framework, has just released version 2.0. Check it out today!
Targeting .NET 4 Client Profile
Support for Silverlight 4
Auto-projecting LINQ queries
Nested/child container support
Map to destination type constructors
Derived type maps inherit base map configuration
They've also removed the dependency on Castle, and the framework is now fully installable from NuGet.
This project has saved me a lot of time I would normally spend manually mapping DAL objects to DTO objects, and has allowed me to cut the size of the DAL codebase down by at least 25%.