Because enthusiasm continues to be so high for the Windows 7 Beta and we don’t want anyone to miss out we will keep the Beta downloads open through February 10th. Customers who have started but not completed the download process will be able to do so through February 12th.
This will give you more than enough time if you want to try the beta. There are good reviews everywhere you look, so if you haven't decided, you are missing out a lot, especially if you are using Windows Vista. It is important to note that product keys will be available even after that
Product keys for the Windows 7 Beta will continue to be available. So if you have the Windows 7 Beta but didn’t get a product key you will be able to do so even after February 12th.
MSDN and Technet subscribers need not to worry about any dates as they will have access throughout the entire Windows 7 Beta phase