I came across this today and decided it was worth sharing. Through community interactions, I understand a lot of folks are still wrestling with deploying Windows 7. This web guide does an excellent job stepping you through the process of upgrading to Windows 7 utilizing MDT 2010.
BTW: If you use Evernote, just clip the guide into one of your Evernote notebooks and carry it around with you on any device. How do you do it? Read this tip: Evernote tip: Creating your own System Center documentation
Also, here’s a cool guide talking about the differences between manual and automated deployments of Windows 7:
Download (PDF): Windows 7 Deployment Options for Small and Midsize Businesses