It seems that i have created a bit of debate, which can only be good for all of us!!
My Rule book, states:
"The Showdown"
1: A player must show all cards in the hand face up on the table to win any part of the pot.
2: If you show cards to another player during or after the deal, any player at the table has the right to see those exposed caards. cards shown during the deal to a player not in the pot should only be shown to all players whn the deal is finished.
3: If everyone checks(or is all in) on the final betting round, the player who acted firstis the first to show the hand. if ther is waggering on the final betting round, the last player to take aggressive action by a bet or raise is the first to show the hand. In order to speed up the game, a player holding a probable winner is encouraged to show the hand without delay. if ther is a side pot, players involved in that pot should show their hands before anyone who is all in for the main pot only.
This is taken from Roberts rules of poker, Which happens to be my name, the author is Robert Ciffone, it came free with a mag.
These would be the rules that we would play in our home game, and i am Known as the TD in, for doing most of the organising!
Good luck all !!!