BDD and MDT releases all the way back to BDD 2.5 available for download in one spot

Although you should probably be using Microsoft Deployment Toolkit 2008 Update 1 (say that five times fast) for any new desktop rollout or DDPS session, the older versions are handy to have around for features/operating systems that get retired/depreciated over time.

If you have a need for any of these versions:

BDD 2.5 Standard
BDD 2.5 Enterprise
BDD 2007
Microsoft Deployment
MDT 2008

You can grab them from here.