Can be purchased from this site. Alohawks!
Tickets are SOLD OUT. There are a handful of tickets available on Ebay. I do think that you'll be able to get tickets outside of the arena, but it's a small place for one, and the folks who have made it there are generally well-to-do, so it might cost ya.
Still, the biggest reason to go to Hawaii to watch, or for that matter, not watch the Hawks, is to get to spend time in Hawaii and have pretty close contact with the players / coaching staff. It's like an NCAA tournament environment, with sand.