What is the job of senate minority leader?

Whether it's the majority whip or the minority whip, this is the person who makes sure members of his or her party are rounded up for important votes; the whip also tries to make sure those members vote the way party leadership wants them to vote. The majority whip is from the party in power; the minority whip is from the party not in power. Currently (2012), the majority party in the House is the Republicans, so the majority whip would be a Republican. The party out of power is the Democrats, so the minority whip would be a Democrat.