If you downloaded ASP.NET MVC 3 Preview 1, Microsoft has also uploaded the source code to CodePlex so you can kick the tires and look under the hood.
Again, this stuff is really early and subject to change, so I wouldn't waste too many cycles memorizing the code.
As mentioned before, you can take a peek at early implementations of the following features in ASP.NET MVC 3:
- Razor View Engine
- Dependency Injection hooks using a service locator interface.
- Support for .NET 4 Data Annotation and Validation attributes.
- Add View dialog support for multiple view engines including custom view engines.
- Global Action Filters
Download the ASP.NET MVC 3 Preview 1 Source Code here.
Related Post: Pro ASP.NET MVC 2 Framework Book Review
David Hayden