Yes, the rumors from several months back were true and now the news is out. TiVo is working with Amazon to bring video downloads directly to the TiVo. You will be able to buy or rent videos from the Amazon Unbox site, and have them download directly to your TiVo. It'd be nice to see ordering directly via the TiVo eventually, completely eliminating the PC - probably developed as an HME application, like TiVoCast and Guru Guides. I think this was the missing piece to Unbox - getting the video to the TV, not the PC. This also gives TiVo another arrow in its quiver to compete with the video downloads for the Xbox 360, the Apple TV, and the coming downloads for the PS3. And it vaults them ahead of download-only services like Akimbo in terms of market penetration as all broadband connected TiVos will have access.
EDIT: There is a FAQ and a form to sign up to be notified when more news is available at http://www.tivo.com/amazon
EDIT2: There is also an Amazon page on TiVo Unbox