As yet I have not been able to download the official Windows 7 Beta1 from the Microsoft website.
Looking at this page on their site, it says:
"Thanks for your interest in the Windows 7 Beta. The volume has been phenomenal—we're in the process of adding more servers to handle the demand. We're sorry for the delay and we'll re-post the Beta as soon as we can ensure a quality download experience."
Still no official download link available?