If you start playing omaha hi, limit, pot limit or no limit .. you'll want to know what the best starting hands are  of course. So here's what are the best starting hands that *I* use in Omaha hi :

AAKK double suited ... best starting hand ever. Although you may even need to fold this one after the flop if it doesn't match up at all.

AKJ10 double suited. Ted Forrest says this is the best Omaha starting hand

Any 2 suited connecters (double suited again of course)

Pair of aces with a suited ace 

Pair of aces with a suited connecter 

High pairs from 8 to K with suited connector

High pairs from 8 to K

Anything else should only be played from late position with no raise pre flop. Then a few basic rules :

When you are drawing, make sure you are drawing to the nuts. Flushes and Full houses are abundant in Omaha, so if you are drawing to a flush, make sure it's the NUT flush. And don't draw to flushes if the board is paired and your opponent is betting into you as he very well might have a full house.

In general, in Omaha, the winning hands are straights and flushes with the occasional full house. Straight flushes, quads (four of a kind) are all much more common than in regular holdem poker.

For playing Omaha, I recommend checking out PokerStars or Full Tilt Poker . You'll find many tables there with plenty of fish.