One of the biggest complaints users had about Vista when it was first introduced, was the lack of drivers or drivers that were problematic. In the hope of eliminating or at least curtailing a similar situation, Microsoft has instituted a policy in which drivers for Windows 7 beta, must be included started June 1, 2008, when submitted for Vista.
Customers have a need to ensure compatibility with the new releases of the OS and that hardware (systems and devices) are fully functional after an upgrade. This will enable Microsoft and partners to evaluate the results and correct issues in the new OS and the associated hardware as part of the release plan.
Beginning with the release of the first beta of the next operating system, all Windows Vista client and Windows Server 2008 submissions must include a complete CPK with test logs for the new beta OS. The test logs generated from the beta OS are not required to pass. Issues with hardware, system BIOS or drivers must be investigated and resolved by partners prior to the launch of the logo program for the new OS.
The tests should be run after performing an upgrade from Windows Vista or Windows Server 2008 to the beta OS. Testing on the new beta OS must be done with drivers that are intended to install on the beta OS.
Design and Implementation Notes
Beginning with the first beta of Windows 7 all Windows Vista submissions must include a complete CPK with test logs from Windows 7. The test logs generated are not required to pass.
I believe that this is a good way to start aquiring the proper drivers for Windows 7 before the final release hits the streets.
Source in .pdf format