Horas / Minutos transcurridos entre dos fechas

select
rtrim(DATEDIFF(MI, '27/05/2013 09:52:00','27/05/2013 11:41:00') / 60) +
':' +
rtrim(DATEDIFF(MI, '27/05/2013 09:52:00','27/05/2013 11:41:00') % 60)