A new update for Office 2007 is out now, called Office 2007 Beta 2 Technical Refresh. It is something like a service pack for the Beta 2 build and extends the validity of the Beta 2 build till we can see an RC1. To install this you will need to have Beta 2 installed first. Also, it is free to download (You dont have to pay the $2 download fee for this, as of now) from the Office Preview Site.
It does take a long time to install and the setup interface is just a progress bar. So make sure you get it started when you go out for lunch..:-)