Like all variations of poker, the object of Hold'em is to make the best possible 5 card hand.

The Game

Each player is dealt two cards face down. These cards are known as the "pocket" cards or the "hole" cards. Then there is a round of betting (see betting below). Players decide to fold, call or raise in turn based solely on the value of those two cards.

The dealer then deals three cards face up in the middle of the table. This is known as "the flop". These three cards are communal cards and are shared by each of the players who remain in the hand. Remember - the idea is to make the best possible 5 card hand, and each player now has their two hole cards and the three on the board to make up their 5 card hand. There is another round of betting, and again players decide to stay in the game or get out quickly based on the value of the 5 cards now available to them.

The dealer then deals one more card face up onto the table. This is known as the "turn card". Each player now has 6 cards to choose from, the four on the table and their two hole cards. A poker hand is only 5 cards, therefore each player chooses only their best 5.
There is another round of betting.

The dealer then deals the final card face up in the middle. This is known as "the river". The remaining players now have seven cards from which to make the best possible 5 card poker hand. A final round of betting takes place.

After all bets have been made, the remaining players turn over their two hole cards, the best hand is established, and the winner takes the money.

* - if at any point in the hand only one player remains, i.e. hasn't folded, that player
wins the pot.

For example:
The dealer deals two cards to each player. Three players call the bet and four players fold. The last player to act in this round of betting decides to bet all of their money (known as going "all-in"). All the other players decide not to risk losing all their money and fold. The player who made the all-in bet takes the pot and wins the hand before any of the communal cards are dealt. The cards are shuffled and the next hand is dealt.

Rankings

The ranking of hands is as follows (from best to worst):

STRAIGHT FLUSH, 5 cards in numerical order, all of the same suit.
5,6,7,8,9 of hearts or 10,J,Q,K,A of diamonds

FOUR OF A KIND, 4 cards of the same value
A,A,A,A,6 or 9,9,9,9,3

FULL HOUSE, 3 cards of one kind and 2 of another
4,4,4,K,K or J,J,J,2,2

FLUSH, 5 cards of the same suit (but not in numerical order)
3,6,9,J,K all clubs or 2,5,8,Q,A all clubs.

STRAIGHT, 5 cards in numerical order but not of the same suit
3,4,5,6,7 all of different suits or 5,6,7,8,9 all of different suits

3 OF A KIND, 3 cards of the same value
5,5,5,10,K or 6,6,6,4,9.

2 PAIRS, 2 cards of the same value plus 2 cards of another
3,3,J,J,4 or K,K,5,5,J

1 PAIR, 2 cards of the same value
J,J,3,2,8 or 3,3,K,6,A

HIGHEST CARD, no pairs
A,5,2,9,K or J,7,4,3,2

Note - If two or more players hold hands of the same ranking then the winner is decided by virtue of their highest card:

Example 1:
Two players hold a flush:
Player 1 has A,K,8,6,7 of clubs. Player 2 has K,4,8,6,9 of clubs. Player 1 has an Ace high flush, player 2 has a King high flush. Player 1 therefore has a higher flush and would win. If both players had an A high flush, it is then necessary to look at the second card to decide who is higher, i.e. A,K,5,8,9 beats A,Q,3,2,8

Example 2:
Two players hold a full house:
Player 1 has 6,6,6,K,K. Player 2 has K,K,K,6,6. Player 1 has a full house of 6's, player 2 has a full house of K's. (It is the three of a kind part of the hand that decides how high the full house is). Player 2 therefore has a higher full house and would win.

Example 3:
Two players hold 2 pairs:
Player 1 has K,K,J,J,5. Player 2 has K,K,J,J,8. Both players have two pairs and are tied with King's high. It is therefore necessary to look at the value of the second pair. Again, both players are tied with Jack's. However, a poker hand is always 5 cards. It is therefore necessary to look at the fifth card. Player 2's 8 is higher than player 1's 5. Player 2 will therefore win the hand.

No suit is higher than any other and suits are never used to decide who has the best hand. Spades do not beat Diamonds, and hearts do not beat clubs.

The above was taken from 4later.com

The odds 5 card draw:

HAND QUANTITY IN DECK ODDS AGAINST

Straight Flush 40 64,973:1

Four of a Kind 624 4,164:1

Full House 3,744 693:1

Flush 5,108 508:1

Straight 10,200 254:1

Three of a Kind 54,912 46:1

Two Pairs 123,552 20:1

One Pair 1,098,240 5:4

No Pair 1,302,540 Evens

Boycie: "What ya got Del Boy?"

Del: "2 Pair ................. 2 Pair of Aces!"