Today at Microsoft PDC 2010 Brian Harry showed a demo of TFS 2010 installed and hosted on the cloud. This is super cool stuff. Because you do not need to install and configure TFS 2010 on premises. Rather you provision the Team Foundation Server and just have your Visual Studio 2010 connected to it. More so, you can also let Yahoo, Google, Facebook connect to your TFS 2010 hosted on Cloud. So people can access using their Yahoo, Google or Facebook user id and password to connect to Team Foundation Server 2010 Hosted on Cloud.
This will also allow you to connect using you domain account. Overall, its super cool stuff.
Watch out more at Brian Harry’s blog for more on how Microsoft developed it http://blogs.msdn.com/b/bharry/archive/2010/10/28/tfs-on-windows-azure-at-the-pdc.aspx