If your organization is just now deploying or about to deploy Windows 7 on the desktop, you need to know about User Account Control (UAC). If you’re coming from Windows XP, this is a new security mechanism that was introduced in Windows Vista. If you’re coming from Vista, you need to know about the changes that have been made. Either way, you’ll want to check out this TechNet article that provides guidance to IT pros for developing UAC best practices for their networks, including configuration of the UAC Group Policy settings.
http://technet.microsoft.com/en-us/library/ee679793(WS.10).aspx