As you all know that Windows 7 beta is out and you can download it easily from here. There was a limit to download only 2.5 Million copies but this limit has been lifted up and you can download Windows 7 Beta without any limit till 24 January, 2009.
Have a look at the Windows 7 Blog.
Here are direct links to Windows 7 Beta (ISO Files) :
ISO for Windows 7 Beta 32-bit (English):
ISO for Windows 7 Beta 64-bit (English):
ISO for Windows 7 Beta 32-bit (German):
ISO for Windows 7 Beta 64-bit (German):
a) Here is a full tutorial on how to install Windows 7.
b) Also download the KB961367 update to fix MP3 corruption bug. Here are the download links for 32 Bit and 64 Bit.
Download Fix (32-bit)
Download Fix (64-bit)