If you are having problems uninstalling as uninstall doesnt work then check this post out. It puts all the stops required to manually uninstall all Office 2007 betas. Here's a snippet:

1. Right-click on My Computer and choose Manage Expand “Services and Applications and then select Services In the right pane, stop the Office Source Engine service if it is running
2. Delete the following registry keys if present: HKEY_CURRENT_USER\Software\Microsoft\Office\12.0 HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Office\12.0 HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Office\Delivery\SourceEngine\Downloads\*0FF1CE}-* HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\*0FF1CE* HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\ose HKEY_CLASSES_ROOT\Installer\Features\*F01FEC HKEY_CLASSES_ROOT\Installer\Products\*F01FEC HKEY_CLASSES_ROOT\Installer\UpgradeCodes\*F01FEC HKEY_CLASSES_ROOT\Installer\Win32Assemblies\*Office12* HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Installer\UpgradeCodes\*F01FEC HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Installer\UserData\S-1-5-18\Products\*F01FEC
3. Find and delete all keys under HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall with a valuename of UninstallString that contains a value with *\Office Setup Controller\setup.exe*

So just a word of caution, the manual procedure is advanced in nature and can trully mess up your machine. No one is responsible for what you do on your system. Follow instructions to the tee. UPDATE: Check out Cannot Uninstall Office 2007 Beta From XP Or Vista? and also test drive the 2007 Microsoft Office release - You are just a few clicks away from a free online test drive of the latest version of Microsoft Office programs. Take them out for a spin in this quick, easy-to-use, browser-based trial experience. The real-time test drive does not require product installation or download—it's the fastest way to try out 2007 Microsoft Office system programs.Click here for Office 2007 test drive page or click here for more Office 2007 BUZZ.