[via Scott Hanselman]
Scott just wrote a nice list couple days ago, of all API source code list of the modern internet services like Flickr, Twitter, Digg, etc. I'll just write down here for later references. too busy playing Windows HPC Server 2008 (HPC v2) for now...
The Weekly Source Code 22 - C# and VB .NET Libraries to Digg, Flickr, Facebook, YouTube, Twitter, Live Services, Google and other Web 2.0 APIs