is the bishop any use

Hello I have seen mate's where the player promotes his pawn to queen (of course) I've even seen promotion's where the opponent promotes a pawn to a rook because anything else is a draw or a knight for a quick mate or check for a trap but has anyone seen a game where a player promotes his piece into a bishop and it was necessary.

I've had a game where my opponent promoted TWO pawns into Bishops. He still managed to mate me eventually.

An artificial position:

http://www.chess.com/article/view/fun-stalemate

A real game:

http://www.chessgames.com/perl/chessgame?gid=1253800

 (The reasons behind the underpromotion become more clear as the game game goes on {to avoid later stalemates}).

Another real game (easier to fathom):

http://www.chessgames.com/perl/chessgame?gid=1287069

Yes, this is sometimes necessary to avoid stalemate. Picture a situation where you need to control a diagonal with a bishop or queen to mate your opponent, but promoting to a queen would stalemate him because of the queen's extra horizontal/vertical square covering.