7.09
It is interference by a batter or a runner when --
(a) After a third strike he hinders the catcher in his attempt to field the ball;
(b) Before two are out and a runner on third base, the batter hinders a fielder in making a play at home base; the runner is out;
(c) Any member or members of the offensive team stand or gather around any base to which a runner is advancing, to confuse, hinder or add to the difficulty of the fielders. Such runner shall be declared out for the interference of his teammate or teammates;
(d) Any batter or runner who has just been put out hinders or impedes any following play being made on a runner. Such runner shall be declared out for the interference of his teammate;
Rule 7.09(d) Comment: If the batter or a runner continues to advance after he has been put out, he shall not by that act alone be considered as confusing, hindering or impeding the fielders.
(e) If, in the judgment of the umpire, a base runner willfully and deliberately interferes with a batted ball or a fielder in the act of fielding a batted ball with the obvious intent to break up a double play, the ball is dead. The umpire shall call the runner out for interference and also call out the batter-runner because of the action of his teammate. In no event may bases be run or runs scored because of such action by a runner.
(f) If, in the judgment of the umpire, a batter-runner willfully and deliberately interferes with a batted ball or a fielder in the act of fielding a batted ball, with the obvious intent to break up a double play, the ball is dead; the umpire shall call the batter-runner out for interference and shall also call out the runner who had advanced closest to the home plate regardless where the double play might have been possible. In no event shall bases be run because of such interference.
http://mlb.mlb.com/mlb/official_info/official_rules/runner_7.jsp