It looks like Microsoft has decided to publish a few product keys to activate all copies of Windows 7 Beta, similar to the same product keys used to activate Windows Server 2008 R2 Beta. The five (5) product keys to activate the evaluation copy of Windows 7 Beta for unlimited times are listed below.
Windows 7 Beta 64-bit Product Key
Windows 7 Beta 32-bit Product Key
So download and install Windows 7 Beta now. No registration is required. Windows 7 Beta DVD ISO media is available from official direct download links
for 32-bit and 64-bit Windows 7 Beta, or x86 Windows 7 Beta torrent and x64 Windows 7 Beta torrent. Note that even after been activated, Windows 7 Beta will still expire on August 1, 2009.