Microsoft released beta 2 of Office 2007 to the public earlier today.
This beta is available for download at
http://www.microsoft.com/office/ preview/default.mspx. In addition to Office 2007, you can download betas for the various Office server products. You will need a passport to sign in for the download.

As with all betas, it's not recommended that you install it on a "production" machine - install it in a virtual machine (virtual pc or
vmware) or on a spare computer as you may need to reformat it when the beta ends. At the very least you should make a disk image (using Ghost or True Image) for quick restoration.

If you choose to use the smart downloader (recommended), the downloaded files can be found at C:\Program Files\LTG\SmartSource for Microsoft Office Downloads\downloads, unless you changed the location.