Basic licensing principles:
* Everyone that accesses TFS data (source control, work items, reporting, report subscription) needs a CAL
* You can buy a retail version of TFS from a reseller (which is included with 5 TFS CAL's), and it is also included in every MSDN subscription.
* Everyone that has a MSDN subscription has also a TFS CAL
* TFS has included a SQL Server license for the sole purpose to install the TFS databases
For more detailed licensing questions you can refer to the Visual Studio 2010 License Whitepaper: http://www.microsoft.com/downloads/details.aspx?displaylang=en&FamilyID=2b1504e6-0bf1-46da-be0e-85cc792c6b9d
Or you can call 1-800-426-9400, Monday through Friday, 6:00 A.M. to 6:00 P.M. (Pacific Time) to speak directly to a Microsoft licensing specialist, and you can get more detail information from there. Worldwide customers can use the Guide to Worldwide Microsoft Licensing Sites to find contact information in their locations: http://www.microsoft.com/licensing/.