OH8 is my favorite game to play, why? There are so many players out there who play it without having a clue what they're doing.
Each player gets 4 cards, and after that everything is done exactly as in Texas Hold'em. However, when you make your hands at the end you absolutely have to use 2 cards from your 4 in your hand. No more, No less. That's the aspect that confuses most players. Other than that, you're playing poker. Remember in Omaha that big hands are the rule. It's a game of fullhouses getting destroyed by other fullhouses, it's very common.
A low pot consists of 5 cards 8 or less, suits aren't taken into account and neither is it if you have a straight although an Ace-5 straight is a powerful OH8 hand. Your low hand cards and your high hand cards don't have to be the same 2 cards from your hole cards....
Hope that helps
Justin