From the betaplace:
The technical refresh includes significant performance improvements and redesigns to address your needs and to enhance your user experience. New features of the Beta 2 Technical Refresh include an updated user interface, better accessibility support, improvements in the robustness of the platform, and greater functionality.
For example, you can now deploy code access security policies with your SharePoint sites, as well as experience TimeZones and TimeZone objects that provide object model support in Microsoft Office Outlook. Look out for the Beta 2 Technical Refresh SDKs as well, which add many more articles and code samples to help jumpstart development.
Please note that the Beta 2 Technical Refresh extends the timeline for Microsoft Office Beta 2 use, which you need to install first. The refresh is also recommended if you’d like to use Office 2007 beta in combination with Windows Vista RC1. In addition, it updates Microsoft Office SharePoint Server 2007 for Search with a simple and powerful user interface, making it easier than ever to deploy and manage this core search for your business. Be sure to visit TechNet Beta Central as well, where you will find resources designed to help you get the most out of your evaluation. These include web forums, bug voting, virtual labs, e-learning modules and news and updates.
The Beta2TR software is available for download at no cost at the Microsoft Office preview site at www.microsoft.com/office/preview. Be among the first to experience these exciting new enhancements.
Beta2TR Product License Keys
Because the Beta2TR build is being provided to you as a patch, you should NOT be prompted for product license keys when installing Beta2TR. If you find yourself needing product license keys (for instance, if reinstalling Beta 2 or installing on a new computer), you will find the Beta-2 volume license keys on the Product Downloads page.
Beta 2 Downloads are still free on BetaPlace
Since most Beta2TR software requires that Beta-2 is first installed, we will continue to provide you with direct downloads on BetaPlace’s Product Downloads of the same Beta-2 installation files found on the Office Preview site. This will enable you to install Beta2TR on new computers and continue participating in the private beta without incurring any download charges. You will need to use the Volume License Keys located on the Product Downloads page for all product installations, as unique keys will not be provided as part of the download process.