In most real-world scenarios, you’ll probably want to deploy to multiple
Windows Azure managed services or subscriptions—for example for test, UAT and
production—and use different configuration settings for each.

This post shows one way to extend Visual Studio 2010 and Team Foundation
Server 2010 to automatically build and deploy your Windows Azure applications to
multiple accounts and use configuration transforms to modify your Service
Definition and Service Configuration files. The goal is to make it easy to set
up as many TFS Build definitions as required, enabling you to build and deploy
to a chosen environment on-demand or as part of a regular process such as a
Daily Build.

Great post by Tom Hollander!