In elementary they taught us this move, but it can only be used when the pawns don't skip the first block in front of them when they are at the starting position, they are allowed to eat the peice in front of them only once. I'm not sure if that move exists or what it's called though.
edit: I think it's something simillar to this http://en.wikipedia.org/wiki/En_passant or possibly something to counter the move, if you have 2 black pawns on d5 and e6, and 2 white ones on d4 and e5, the black pawn on d5 could directly eat the d4 pawn before the e5 eats the d5 with en passant.
Here's an example with the positions I posted http://en.wikipedia.org/wiki/Pawn_%28chess%29#Strategy
But then again I think it's a matter of who gets to the en passant position first.