If you happen to be trying out Team System with all its bells and whistles you really should apply a modified version of "Develop with Least Privilege" or whatever it is called.  Only, with Team System you should use a "Least License" approach if you want to be kept aware of the licenses you'll actually need.

I'm writing this, as I just became aware that in order to run your unit tests as part of a Team Build you must first set up a Build Verification Test (BVT) list.  Setting up a BVT requires that you have VSTS for Testers (or the full suite).  So at the end of the day you will never be able to do much quality software development (never mind architecture) without both the Developers and Testers editions.  And the latter you may need only to set up the BVT.  (The other functionalities of Tester we don't need as Mercury TestDirector is already in place and doing fine.)

So, Microsoft, maybe this packaging should be up for reconsideration? 

Nothing exiting here, but just found out how to initate a Team Build in Team Foundation Server beta 3.

As I was able to figure out from elsewhere, pre-beta3 builds were done using some more or less homegrown code to construct an executable for scheduled builds.

That has appearently changed with TFS beta 3.  Now you schedule TFSBuild.exe using the right parameters as desribed in the documentation (Use the start command).  This part of the documentation is not - as far as I can tell - part of anything you get on disk and MSDN download at the moment.

(Note though that the documentation has the command named teambuild, but its actaul name is TFSBuild and is located in ...\Microsoft Visual Studio 8\Common7\IDE)