Omaha 8 is omaha played for hi/lo split, as stud8 is to stud. The pot is split two ways between the high hand and the low hand. To qualify for low, you need 5 cards including or below an 8, including aces and excluding pairs. You count low hands from the high card down, so 76543 beats 8432A. Hands can split the pot for high or low, and it is common in multiway pots for the low to be split (quartering - i.e. the low only wins splits half the pot, so gets a quarter).

On a board 67K4Q, if there are three hands involved, KK55, A2QQ and A268, the KK55 wins high and thus takes half the pot, both the other hands have A2 in hand and 467 on board for A2467 low and thus split the low, both winninng quarter of the pot. It is therefore advantageous for the guy winning half the pot to put in as much money as possible and the other two to get to showdown as cheaply as possible, though in general the guy with A2QQ is likely to be raising like hell too as he has a strong high hand to go with his low. However, if the board shows 67KQQ, there is no qualifying low hand as there are only two low cards on the board. KK55 wins the whole pot.

The Ciaffone book is a good one for an omaha neophyte, as it takes a straightforward approach to describing hand values & hand reading, starting hand selection, how omaha differs from holdem, and fairly straightforward post flop play that'll be good enough to beat most weaker PLO games. You're better off starting with PLO (high only) instead of PLO8, as playing a new flop game (omaha) which ALSO has a split is going to be unnecessarily complicated.

As far as starting hands and some fairly simple post-flop plays go, I wrote a couple of articles a few years ago that are on the front page of BTP. I don't 100% agree with everything I wrote now, I am a bit more loose preflop in certain situations for instance, but I think it's mostly sound advice. Would be well advised to look at the starting hands article especially, you can be more relaxed with starting hands in PLO than you can in NL but bad hand selection when your post-flop play is still developing or you're not sure what you're doing in many situations can feed some serious post-flop leaks when you're trying to get a feel for the game (drawing routinely to non-nut hands for example).

Ha! So THAT'S what the 8 stands for!
Thanks again for your answer...here's an article i found online...how good is it? Is it a beginner's guide? If i learned all this, would i beat most PLO high games out there?

http://www.pokerlistings.com/pot-limit-omaha

Sorry, if you would, one more question...if one learns to play PLO well, will it mess up your NL hold'em game a bit? (as in learning LIMIT hold'em messes up your NL hold'em game a bit)