Taylor Lafrinere, a developer on Team Foundation Server who wrote a significant part of the new core server infrastructure APIs, has written a series of posts explaining some of the different parts.  If you have other parts of the API that you are interested in, be sure to leave a comment on one of his posts.

Here are a few of his posts to get you started.

• Introducing the TfsConnection, TfsConfigurationServer and TfsTeamProjectCollection Classes
• Retrieve the List of Team Project Collections from TFS 2010 Client APIs
• Introducing TFS Impersonation