Updated: I got up before 5am to try this. There were flights available, just nothing that worked for me for same day travel.
Go! Airlines is celebrating its third anniversary. Gosh the time went fast. 
To celebrate, they are offering one thousand $3 (plus tax/fees) inter-island tickets starting today at 5:00am (Hawaii time). Tickets will be valid for travel between June 9 and June 30 only (not available Friday-Sunday). Three lucky people will also win free round-trip tickets.
These will go fast. I intend to get up at 5:00am myself, and see what I can do.
Let us know how you fare!
PS: If you are getting this in email, please consider changing to RSS in order to receive these deals timely.
Get Breaking Hawaii Travel News
Hi Courtney.
It is wise to book well ahead of time, as indicated in the current inter-island deal thread. Otherwise you may well not find your desired flights available, or if they are available, it may well be for substantially more money.
Aloha, Jeff
Jeff- I know this deal has passed, but do you have suggestions for a visitor who would like to do inter island travel while on Vacation in Hawaii? Is it wise to book ahead of time, or is it the same price to do it at the airport on the day of travel?
Thank you!
I was just wondering what to blog about on Best Hawaii Vacation blog today and came across your tweet! That’s some great info. I got to rush to get it out.
I will retweet + write short blog info for my blog visitors as well.
Much mahalo! Aloha, Pua
Best Hawaii Vacation Blog
Welcome Pua. I felt disappointed to get up at 5am and find such limited availability. You’d need to have been very flexible on your dates and times to make it work.
Aloha, Jeff