You have the choice of air-conditioned coaches or open-air buses with canvas flaps in case it rains. Local bus stops can be found in every town - but you can hail any public bus simply by waving to the driver.
The Coral Sun Express bus offrs frequent service from the Airport to Nadi and beyond, including restorts & hotels. For timetable open http://airportsfiji.com/pdf/ExpressTimetableAFL.PDF
The Sunbeam Transport via Queen's Highway offer frequent express buses to/from Lautoka / Suva. For timetable & fares open http://airportsfiji.com/pdf/Sunbeam_timetable.pdf
The Pacific Express runs between Suva, Navu, Pacific, Sigatoka, Nadi & Lautok.
The Classic Bus runs between the Airport and Votualevu roundabout.