They have a few times, but not in the Super bowl.
Yes, they have. Through 2010, the Steelers have beaten the Patriots 13 times in the regular season and once in the playoffs.
The Cowboys defeated the Patriots seven times - the Patriots have won the last four meetings.
The Patriots have beaten the Steelers three times in the playoffs.
The New York Jets have beaten the Patriots more than any other team in the League. They have beaten New England 52 times.
Patriots, 49ers, Steelers
The Broncos, Jets, and Colts.
No. Baseball players generally do not play games with football teams.