There’s a nice little flash based demo on the web about DSI (you’ve got to press the ctrl key when you download it, as it runs in a pop up window). It’s very animated :-).
I present this session quite often, and this demo covers all of the fundamental concepts you need to know – especially if you’re not too familiar with Visual Studio 2005 Team System. Christian points to some useful links about the SDM and VSTS to get you up to speed
You can also find other links from the DSI home page.