@Pablo: "Bancada" es el nombre informal (me acabo de enterar). Oficialmente se llaman Grupos Parlamentarios y cada jefe tiene el título de "Coordinador de Grupo Parlamentario". Creo que eso es un poco más genérico, aunque no apuesto a que sirva para otros países de cualquier manera.
@wrholt: I don't think we have these equivalences in Mexican Congress.
I hope this will answer your question, but if I misunderstood, let me know.
US Congress = Congreso General / Congreso de la Unión
House of Representatives = Cámara de Diputados (the media also call it Cámara Baja)
Senate = Cámara de Senadores / Senado (the media also call it Cámara Alta)
Each "cámara" has a "Presidente" (I think these are the Speakers). In the Senate, the "Presidente" governs with a "Mesa directiva", where members are elected by the whole "cámara". In the House of Representatives, the "Presidente" governs with a "Junta de Coordinación Política", where each member is the "coordinador" of each "grupo parlamentario".
Since we have many more than two political parties (this time they're 7, but we've had 9 and the number changes with every election), we don't have a majority and minority relationship. Our "grupos parlamentarios" or "bancadas" correspond to the congresspeople belonging to each political party. Each one of these groups have a "Coordinador" who leads them and tells them what to vote, how and when; that is why I think that these "coordinadores" are equivalent to the "chief whips".