You'll probably get some better responses in "Other Poker"; there seem to be quite a few Omaholics in there.
Personally i just logged my knowledge of the O8 book market
here. Be advised that Zee is rather more advanced, if i'm not mistaken.
For poker-savvy O8-beginners i think Tenner and Krieger have the best reputation, but i've only browsed that book in a bookstore.