It's the theme song of the Czech Area Concertina Club:
It also goes by the name, "Farewell to Prague", or "Kdyz Jsme Opustili Prahu" in Czech.
It still remains popular under the name "Shiner Polka". Here's a version by a band called Cracker, apparently not the San Francisco band Cracker that I know - -
Here's the sheet music, courtesy of ConcertinaMusic.com --