TechNet, MSDN and Techbeta customers can download it now.
Consumers who want to test-drive the beta will be able to download it beginning Jan. 9 at http://www.microsoft.com/windows7 .
Here is the full press release:
Microsoft’s Ballmer Announces Availability of Windows 7 Beta and Windows Live
For TechNet, MSDN and Techbeta customers it is already available here;
Windows 7 Beta 64-bits (Download also this MP3 Fix !)
Windows 7 Beta 32-bits (Download also this MP3 Fix !)
Release notes Windows 7