If it's serious poker you're dealing with, then your responsibilities are:

1. Proper shuffling of the cards.
2. A proper deal, in the proper order, giving each person the proper number of cards.
3. Keep the bottom card of the deck hidden by using a cut card. The dealer should not expose any cards that are in the deck that shouldn't be shown during game play. A misdeal ticks off everyone at the table, so the dealer shouldn't mess this up. Don't give anyone any additional information that they shouldn't know.
4. Dealer should keep track of the buttons, depending on the game. If using a dealer button, small blind button, and big blind button, the buttons need to be properly rotated (again, to the left of the last dealer). This ensures that no one misses a blind and doesn't pay their due. If you're not using buttons but are using antes, be sure that everyone places their ante before the cards are dealt and be sure it's the right amount.
5. The dealer should re-announce the player's actions. If a player raises, the player usually will say "call" or "Raise", but in some casinos, people can just place twice the bet and it implies a raise. Because of this, the dealer has to pay attention to the action and the amount raised. If the player raises $4, the dealer should say "Raising 4 dollars", then the dealer moves his attention to the next player to the left of the raiser. Some dealers will actually point towards the next player (with your index finger extended and you hand on the table, don't point in the air across the table) or some may tap the felt in front of the player. When this is done, the dealer can tell the player how much it is to call. For example, if the four dollar raise makes it $8 to call the player, the dealer would point to the next player and say "$8 to call".
6. Once the bet or raise has been made, it is the dealer's responsibility that anyone who is not in the hand folds their cards to the dealer. Also, make sure that no one at the table has been skipped during the course of play.
7. Dealers should collect all folded cards, then pull the pot money towards the center of the table so that any future bets do not get lost in the main pot.
8. Dealers should keep track of all action and keep it moving. If working for a casino, the casino takes a "rake" from each pot to keep for the house's benefit. If the rake is 10% and the pot is $100, the dealer is responsible for taking $10 out of the pot and placing it in a rake box so that it cannot be taken back out again.
9. Dealers are sometimes responsible for announcing the winner of the hand, though some houses allow the cards to do the talking.

Additionally, dealers have to:
1. Assist players who aren't sure of the winner, and be able to explain why the hand was one. In Texas Hold 'Em, for example, on the top 5 cards win, not the top 6. People often get in arguments when two players both have made a straight, but think their sixth card should determine the winner. This is not the case. A good dealer should be ready to read the rules according to Hoyle to these people and let them know why the pot was split or why one or the other lost.
2. Split pots - be able to add, stack chips, split the pot equally.
3. Side pots - when one player has fewer chips than others, that player may be able to only take a smaller pot. This would cause a side pot to be in play, which is often the responsibility of the dealer to set that pot to the side and remind the short player to not turn over his cards until the others have concluded play.
4. Cashing chips - taking the money from a player and exchanging a proper amount of chips to the player.
5. Allowing the "eye in the sky" to view money coming from the box to the player. You just can't take a players money in a casino. The money has to be laid on the table so the cameras can see it, or the poker room boss can see it. When the money is passed to the player, the dealer usually has to present the chips in such a way so that superiors can see the proper amount was exchanged.
6. Keep track of having an adequate amount of chips in the dealer's chips box.

Official rules of poker…depends on the game. Check some websites for the official rules.

If you're interested in dealing in Vegas, just apply for a job. Just know that you're not likely to be dealing at the Bellagio for your first job…it takes time, unless you know someone who can streamline you in. I've seen plenty of dealers in Vegas who don't know how to properly run a poker table, and it seems they get new dealers every month, so I am assuming it's not as hard as it once was.

Have fun…hope this helps!!!

However, friendly home games are a bit different. If it's truly a friendly game, it's often better to let slight breaches in etiquette pass without saying anything. Few people enjoy playing for micro or low stakes with an enforcer at the table. If the players are more serious about the game, then your comments might be better appreciated.

Texas Hold 'Em (or Texas Holdem) is the version of Poker played in many casinos, and seen on the Travel Channel's World Poker Tour and ESPN's World Series of Poker. These are the basic rules for Texas Hold 'Em Poker.
The Shuffle, The Deal and The Blinds

The dealer shuffles a standard 52-card deck.

(In casinos, the dealer never plays. A round disc — known as a "dealer button" — moves clockwise from player to player with each hand. The button marks which player would be the dealer if the deal were advanced from player to player as the game went along.)

Most Texas Hold 'Em Poker games start with the two players to the left of the dealer (the button) putting a predetermined amount of money into the pot before any cards are dealt, ensuring that there's something to play for on every hand. This is called "posting the blinds." Most often, the "first blind" — the player to the left of the dealer — puts up half the minimum bet, and the "second blind" puts up the full minimum bet.

Each player is dealt two cards, face down. These are known as the "hole cards."

Betting Begins

A round of betting takes place, beginning with the player to the left of the two who posted the blinds. Players can call, raise, or fold when it's their turn to bet.

The Flop

After the first betting round, the dealer discards the top card of the deck. This is called burning the card and is done to ensure that no one accidentally saw the top card, and to help prevent cheating.

The dealer then flips the next three cards face up on the table. These cards are called the "flop."

NOTE: Eventually, a total of five community cards will be placed face up on the table. Players can use any combination of the community cards and their own two hole cards to form the best possible five-card Poker hand.

After the flop, another round of betting takes place, beginning with the player to the left of the dealer (the button). During this and all future rounds of betting, players can check, call, raise, or fold when it's their turn to bet.

Fourth Street

The dealer burns another card and plays one more face up onto the table. This, the fourth community card, is called the "turn" or "Fourth Street."

The player to the left of the dealer (the button) begins the third round of betting.

Fifth Street

The dealer burns another card before placing the final face-up card on the table. This card is called the "river" or "Fifth Street."

Final Betting and The Winner

Players can now use any combination of seven cards — the five community cards and the two hole cards known only to them — to form the best possible five-card Poker hand.

The fourth and final round of betting starts with the player to the left of the dealer (the button).

After the final betting round, all players who remain in the game reveal their hands. The player who made the initial bet or the player who made the last raise shows their hand first.

The player with the best hand wins.