I finally got round to installing Beta 2 - Team Suite. I followed these instructions before starting the install. The initial install failed with this entry in the MSI log:
MSI (s) (18:8C) [22:17:27:358]: Note: 1: 1708
MSI (s) (18:8C) [22:17:27:368]: Product: Microsoft Visual Studio 2005 Team Suite Edition Beta 2-English -- Installation failed.
The second install worked, but all the Testing functionality appeared not to work, so now I'm doing a third install.
Update: Based on the Testing not working, I cleaned my testing machine, re-installed Windows XP, and re-installed VS 2005 Beta 2 - Team Suite.... and got the same error message: Package 'Microsoft.VisualStudio.QualityTools.TestCaseManagement.QualityToolsPackage....' failed to load property. These issue is actually documented in the VSKnownissues.rtf - Issue Team Developer and Test tools do not function if Team Foundation Client is not also installed.