IMF eLibrary Data. On the landing page, scroll down toData by Indicatorand selectInterest RatesunderInternational Financial Statistics.Use the tabs and drop-down menus to tailor country, date, and periodicity (Annual, Quarterly, Monthly).
Bloomberg (MIT Sloan only): Type MMR and hit the green GO key to access the Money Rate Monitor.
Datastream available in Dewey Library, workstations 5 and 6