Ciaffone's Omaha book has a good table that lists certain hand's and the action he would take would them. I think this is a good place to start. Crockpot has a site at
www.winningonlinepoker.com that also has a good guide.
You're going to hear many different ideas on preflop play and I think alot of them work. The reason being that most preflop raises aren't for the pure sake of expectation as is the case in limit hold'em but many are made for positional and deception purposes that dictate how the later streets are played.