The blog on Office 2010 - "The Microsoft Office 2010 IT Blog" was launched by the Office product group earlier this week. Subscribe to its RSS feed or check it regularly to get the official word on the product and release information. They have already posted on the system requirements, some name and SKU changes.
The Technical Preview is coming in July 2009 and Office 2010 The Movie website has the countdown and the Technical Preview invitation sign up link. You can sign up here to be considered for the Technical Preview Program. More details are here: The Microsoft Office 2010 Technical Preview.