Microsoft's developer division has been making a lot interesting moves lately. They're starting to finally listen to the strong thoughts and opinions coming out of the Java converts in the .NET community and realizing they know what they're talking about. As usual, they're not really innovating, but they're taking existing ideas and building some great tooling around those ideas and delivering them to the masses.
In the March release of MSDN Magazine they published Loosen Up which is a general overview of the benefits of IoC and DI. Just last week Microsoft Pattern's and Practices group released Unity - their entry into the IoC and DI space. Inversion of Control Containers and the Dependency Injection pattern are not new ideas and with Castle Windsor, Spring.NET and StructureMap there are many seasoned IoC offerings out there already.
I've been a big fan for StructureMap for it's simplicity. From my initial experience with Unity, it has that same thinness and simplicity. Now that it's from Microsoft, hopefully the Morts will start to pay attention to some of these important design concepts.
David Hayden has a pretty great overview of Unity in screencast form here. Download it and play it in Windows Media Player at double the speed (a handy trick I picked up from Scott Hanselman)