Property managers can also help (be aware, there are some more than scary looking rentals here)
9 years ago, we had very good luck using Erik Birkholm with Aina Realty in Keaau,(808) 966-7464
Also have to recommend John Dirgo (forum Member) with Aloha Coast realty (808)965-9903
http://www.alohacoastrealty.com/
there is one thing to remember, most every real estate agent here will be hesitant to call a "blind" out of area code telephone number (even if you ARE here).
If you do call, make sure that every one you talk to & any message makes it very clear that you HAVE a moving date. (even then, there may be some hesitation - more than a few that plan to move here & never make the trip....and they get those calls & look for properties...etc...)
It is practical to look first at a vacation rental (esp. the first week or two) and really take a vacation here (I know, most every one, including us, want to hit the ground running....but you will find that is definitely not the best way to get things done here....it is a very different kind of place, in regards to business-type endeavors)
There are vacation and long term rental owners on this forum, most have bylines or do post availabilities here from time to time, and it might help to do a forum search (again, it seems strange to ask you to search, but many may miss your post & replies & there are always those ones that plan to move here & never make the trip... )
ADD: if you do call either of the above, you can always drop my name (Erik may be a bit more fuzzy but Carey & Jim from Keaau should help)