At Microsoft PDC 2010 Brian Harry showed a first preview of TFS 2010 installed and hosted on the cloud. Hosting of ALM in the cloud is a great example of software as a service. This making it really easy to get started with Team Foundation Server. Note that this is not a final product and no details were revealed about release date and pricing.
Read more at Brian Harry’s blog: http://blogs.msdn.com/b/bharry/archive/2010/10/28/tfs-on-windows-azure-at-the-pdc.aspx