The TFS Datawarehouse schema is well documented here
As an example, let's say we wanted to get this kind of data in the following form into Excel.
We can use the following SQL statement.
Select IterationPath, StartDate, FinishDate from DimIteration order by StartDate, IterationPath
This yields as follows:
If we were to create new iterations, we can process the Warehouse immediately through a web service. Select ProcessWarehouse link from the following URL.
This provides the following screen.
Finally, use the following link to use the query to populate an Excel spreadsheet.