Chess Club Party Winner

Here is the winning puzzle submitted at the 2003 Chess Club end of season party by Scott Waring. It is a clever one move checkmate.

White to play and win.

8 Black Queen (Q)         Black King (K) Black Rook (R)  
7               White Rook (R)
6   White Pawn (P)    
5 Black Pawn (P) White Bishop (B)    
4 White Pawn (P)            
3          
2             White Pawn (P) White Pawn (P)
1             White King (K)  
A B C D E F G H

This is a clever discovered check. Can you spot it ?