These rules apply to bingo, played in Halls or online, in The United States of America.  There are different rules for just about every nation, for instance The United Kingdom and Austrailia each have their own versions.

U.S. Bingo Rules

• The Card – Each player buys, or is given at least one 5×5 playing card with randomly selected numbers filled out.  There are 25 boxes marked off on each bingo card, with each coordinate housing a separate code like b4 and g57, except the center, which is left open, the so-called “free space”.  The “Free Space” is in the center, and every player starts with this advantage.  Each card is different, so nobody in the Bingo Hall gets the same card.  There are over 9,000 combination of numbers available, so there’s no reason you should have to share your prize because of a duplicate card.
  

  Here's a standard Bingo card

• The Game - A “Caller” usually spins a wheel and randomly selects a ball from said wheel to call.  The caller gives the code, such as b12.  In many halls, a video board helps to give a visual, but if not, the caller will call out the number several times, and your neighbors will be glad to help if you have trouble too.  If the caller calls a number you have, you mark your card (if you have a paper card you x or stamp it, if you have a plastic card youll put a chip over it).  This continues until a winner is determined.
  

  Bingo Caller "calling" bingo

• How To Win - Obviously the object of Bingo is to win, right.  Well, its simple. To win the game you must mark numbers in a horizontal, vertical or diagonal pattern across the card.  That’s right, 5 numbers across a row or column or diagonally across the card means you win.  Its time to call BINGO!!!
  

  Bingo is a FAMILY game!

More on How To Play the Bingo Game

The beauty of this game is you can play, in most cases, as many different cards at one time as you can handle.  Want to buy 10 cards?  You just increased your chance of winning 10 times.  That’s a helluva return on investment!

Don’t be afraid to strike up a conversation with your neighbor when you’re playing bingo.  If you’re online, use that chat feature.  Almost every player we’ve come into contact with has been very nice and helpful.  Its amazing that in bingo, your opponents actually root for you too.  You won’t see this in slots, or any other game for that matter.

Most of all, have fun! – Never take it too seriously, that should have been rule #1.  Never blow more money than you can spend.  Never feel like you just need one more card.  If its not fun anymore stop playing!

Here’s more resources for U.S. Bingo Rules

Bingo Rules Org – These guys also give you some good info on Bingo Rules.

How Stuff Works – Here’s one of the most in-depth bingo rules site available.  Heavy on detailes and etiquette.

Classic Casinos – This site lists some good alternative bingo games like “bingo blood sweat and tears”