Listed here for you are the different poker hands,  ranked from greatest to least,  and the chances of getting any of them.  We've omitted Five of a Kind,  since this hand is only made with wild cards,  and frankly,  we find that kind of odds calculation too exhausting.  
You must assume,  for the chart Odds of Getting These Poker Hands,  that the odds apply to a pat hand -- the original 5 cards a player was dealt,  before he replaces any of his cards.  The true odds of getting a particular poker hand change dramatically once you discard and replace,  and they change with the particular poker game or variation you're playing.  For a clue to how much,  look at the difference between how the 5 and the 7-card games,  in how many ways it is possible to make up a Straight Flush.  In a 50-card game,  there are 40.  In a 7-card game,  it jumps to 41,584.

1.   Royal Flush:   This hand is a Straight  (five cards in succession,  like 2-3-4-5-6)  AND a Flush  (all cards of the same suit)  which has an Ace high,  meaning its highest card is the Ace,  and includes King,  Queen,  Jack,  10.  It is the highest Straight Flush possible.

2.  Straight Flush:  Five cards in order,  all of the same suit.  There is one kind not permitted;  and that is using the Ace in the middle of a straight.

3.   Four of a Kind:   A poker hand including Four cards of the same rank,  like four Jacks.  If two players in a game each had Four of a Kind,  the higher four wins.

4.   Full House:   A poker hand consisting of a pair and three of a kind.  If two players had Full Houses,  the player who had the higher three of a kind wins.

5.   Flush:  A poker hand in which all cards are of the same suit,  either all Diamonds,  all Hearts,  etc.  If two players had Flushes,  the one with the highest card in his hand wins.

6.   Straight:   A hand of five cards that may be of different suits but running in ranking order,  such as 4-5-6-7-8.

7.  Three of a Kind:   A hand including Three cards of the same rank,  as in K-K-K-4-7.  If a second player has Three of a Kind,  the higher ranking set of three cards wins.

8.   Two Pair:   A hand including two cards of the same rank,  and two cards of another rank,  such as 6-6-2-10-10.  If another player had Two Pair,  the one with the highest ranking pair wins.

9.   Pair:  A hand including two cards of the same rank,  as in 8-8-K-2-Q.  If a pair is the best hand,  and more than one player has a pair,  the highest rank pair wins;  if two players have the same pair,  such as 3-3-K-7-4,  and 3-3-8-A-6,  the one with the highest other card besides the pair wins.  In this example,  the one with the Ace in his hand wins.

10.  High Card: When no one has a pair or any other better hand,  the one with the highest card wins.  If more than one has that high card,  then the second highest wins.  Or third highest,  if more than one player has the same two highest cards.

Odds of Getting These Poker Hands in Games Using 5 Cards

Royal Flush 1: 649,739

Straight Flush 1: 72,192

Four of a Kind 1: 4,164

Full House 1: 693

Flush 1: 508

Straight 1: 254

Three of a Kind 1: 46

Two Pair 1: 20

One Pair 1: 4

No-Pair Hand 1: 2

Ways To Make These Poker Hands in Games Using:

5 Cards          7 Cards

Straight Flush     40      41,584

Four of a Kind      624      224,848

Full House     3,744      3.473,184

Flush      5,108      4,047,644

Straight      10,200      6,180,020

Three of a Kind      54,912      6,461,620

Two Pair     123,552     31,433,400

One Pair     1,098,240     58,627,800