Customers will be able to download the beta release of Windows 7 until February 2009. After that date the download will no longer be available.

From the Windows 7 Team blog:

The shutdown of general availability for the Windows 7 Beta will occur in 3 phases over the course of the next few weeks:

  • Starting January 27th, the Windows 7 page will be updated with a warning that time is running out on downloading the Windows 7 Beta and that we will be limiting downloads shortly. People will be encouraged to register and start the download of the Windows 7 Beta sooner rather than later.
  • February 10th, new downloads of the Windows 7 Beta will no longer be available. People who have already started their Windows 7 Beta download and have not yet finished will still be able to finish their download and are encouraged to do so.

You can find out more information here and you can download the Windows 7 beta (until February 10th 2009) from here.