Right now there are airfares from ATL to MBJ for $254 RT, including taxes and fees! Travel must be between 11/20 and 12/14, and there are some dates with no seats available, but still that's a great fare.

Not as cheap, but still good fares also have been announced for the Jan-Feb period.

http://www.airjamaica.com/specials/SpecialsSearch.aspx?searchType=city&origCity=Atlanta&destCity=Montego%20Bay