Update 10/30/2009 3:47 AM EDT: Intel has since released official chipset drivers for Windows 7. They can be found here.
Fresh on the heels of Windows 7-compatible Intel chipset drivers comes a functioning set of AHCI/SATA drivers!
Courtesy of Station Drivers, this December 12 (quoi?) edition of Intel’s Matrix Storage Manager driver uses version number 8.7.1.1001 and features WHQL certification. You may notice that this version number is ahead of the January 9 v8.7.0.1007 driver that Intel still promotes for boards using the ICH8x, ICH9x and ICH10x southbridge/PCH. The following operating systems are supported:
Windows XP family
Windows Server 2003 family
Windows Vista family
Windows Server 2008 family
Windows 7 family
Download: Here