Those who register to participate in the Windows Vista CPP will be able to download Windows Vista Beta 2 and Windows Vista Release Candidate 1 (RC1 – scheduled to be released late 2006) in full download. But beware that full download of Windows Vista Beta 2 is about 3.5 gigabytes (GB) for the 32-bit edition or 4.4 GB for the 64-bit edition, and the file – an ISO image – needs to be burn to a blank DVD media with DVD writer. Or you can pay a nominal fee to get the bootable Windows Vista DVD kits to send to you.
Beta 2 and RC1 of Windows Vista are a time-limited software, meaning their lifetime is expired on 1 June 2007. After that you have to re-install your Windows operating system with Windows Vista release version. Beside, you may not be able to upgrade your installation of Windows Vista Beta 2 (or RC1) to the final, commercially available edition of Windows Vista.
Download Windows Vista from Get Ready for Windows Vista (expired). You can only install Windows Vista by clean installation or upgrade an existing installation of Windows XP. Note that registration for Customer Preview Program may be closed.
Caution from Microsoft:
This is beta code and should not be used in a production environment or on a main machine in the home. Beta 2 is intended for developers, IT professionals and technology experts to continue or begin their testing of Windows Vista. Before you decide to use Beta 2, you should feel comfortable with installing operating systems, updating drivers, and general PC troubleshooting. Some risks of using beta operating systems include hardware and software incompatibility and system instability. If you have concerns about installing this beta software on your computer, we encourage you to obtain the final release version of Windows Vista when it is available in 2007.
Update: Downloads for Windows Vista RC1 has been released.