Here are the download links for ASP.NET MVC 3 RTM:
Be sure to read the release notes for the breaking changes since Release Candidate 2
The Microsoft SDK for Facebook Platform has reached version 3.0 and is now officially supported by the Facebook Development Team. The team recently announced this on their dev-blog, which is great news for all .NET developers wanting to develop applications against the Facebook Platform.
..This SDK contains rich social features and offers something for almost any kind of Facebook developer who is building with Microsoft technology, whether you’re implementing Facebook Connect or are building a Web-based or desktop application…
Microsoft has also supplied a great SDK Overview that will get you started with facebook development in technologies like Silverlight, WinForms, WebForms /ASP.Net, ASP.Net MVC. There are several examples along with the documentation that should be more than sufficient to get the ball rolling.