, or Omaha Holdem as it is sometimes refered to, is just like Texas Holdem
a community poker card game. Infact both of the games are more or less identical in play.
Omaha is played in two variations, one where the goal as usual is to make the best high hand, and one called "Omaha 8 or better" where the best high hand splits the pot with the best low hand, but none of the cards in the low hand can include any card higher than an 8. Omaha "high" is especially popular in Europe when played as pot-limit.
The betting rounds and all other aspects of Omaha are identical to Texas Holdem with the following exceptions:
1) Each player is dealt four hole cards instead of two.
2) At showdown each player's hand is the best he can make by combining exactly two of the four cards in his hand with exactly three of the five on the board. This is unlike Texas Holdem where each player can use both, one or none of his hole cards at his own discretion.
In "Omaha 8 or better" each player also makes a separate low hand if he has access to five cards which are 8 or lower. Note that the best low hand is ace-to-five, which is of course a straight but when determining low hands straights and flushes are normally not considered as existing at all. This goes for all high/low split games.
The best online poker rooms for Omaha Poker are Party Poker
and Poker Stars