Microsoft is going to provide more collaboration utilities for its developers. Yes, at present we see SharePoint, and Team Foundation Server as two key products. I have been using SharePoint for a few months and it serves well. But I do not try TFS.
Team Foundation Server and Team Explorer
In my point of view, TFS is an enterprise level alternative of Visual SourceSafe (sometimes Visual SourceDangerous). Because CodePlex.com is hosted on TFS, I believe TFS is much stabler than VSS.
If you are using TFS and Visual Studio non-Express version, you must try Team Explorer somehow. Yes, TE integrates into Visual Studio perfectly, which makes life much easier.
If you use TE already, you know it cannot be used outside Visual Studio. Yes, generally speaking, for Java, GCC, Delphi, Python, Perl, Ruby guys out there, they cannot use TE or TFS. What a pity! I not yet see some easy-to-use SCM GUI product on open source land.
Teamprise, who provides standalone Java client for TFS built on Eclipse RCP, becomes an important player here.
Yes, I am using Visual Studio Express, SharpDevelop, and CodeGear Delphi, but I can now use Teamprise Explorer to access CodePlex.com server easily. And after trying it for a few minutes I start to love it, which reminds of Borland's (original Starbase's) StarTeam, another great SCM product.
Why Microsoft does not provide a standalone client such as Teamprise Explorer? You know why, don't you?
By the way, you have to pay for Teamprise TFS clients, except that you use it to access CodePlex.com as I do. CodePlex authors can request a complimentary license code from Teamprise. You can find more information on CodePlex.com and Teamprise.com.