Yesterday Steve Ballmer announced the public availability of the Windows 7 Beta. Customers with access to MSDN can begin downloading now and using ImgBurn to burn the .ISO to start installing.

For those that don't have access to MSDN, head over to the Windows Team Blog for information on downloading the Windows 7 Beta publically.

The Windows 7 Beta only supports Windows Vista SP1 to Windows 7 upgrades. So if you intend to do an upgrade – be sure it is on a PC running Windows Vista with Service Pack 1. We are not yet announcing anything regarding finalized upgrade paths for Windows 7.

The Windows 7 Beta will be only available in one edition, which is roughly equivalent the Ultimate edition of Windows Vista.

Also, another important thing to keep in mind is that the Windows 7 Beta will expire on August 1st, 2009.