For those who are staring at the incoming tsunami called Windows 7, here are some resources that might help get you going.
There will be more to come, but this is a good start...
Here is a link to the general philosophy around how to pull off a Windows 7 migration or namely, the 7 Steps to Windows 7.
and here is a link to a technical whitepaper on using DS 6.9 SP3 for a Windows 7 migration.
Be sure to check out general Symantec Windows 7 support site at Symantec.com.