For the out of towners:  Search www.orbitz.com, www.travelocity.com and www.expedia.com for best airfare, hotels and rental cars.

http://flights.sidestep.com/air/ is good too.

When booking a car, try these codes:

Enterprise:  368A6179  (University of Hawaii Corporate rate)

Budget:  T055338  (University of Hawaii Corporate rate)
(800) 527-0700 (reservations)

Alamo:  65551  (University of Hawaii Corporate rate)
Rate Code: X00082

Kama-aina rate code (Alamo): K9BD (try this one too, see which one is better)
 

If you're going to use the UH rate codes, then you need to BS them into believing you work for UH (shouldn't be too hard).