The first place you should check is
the DCCA to make sure you don't step on the toes of a legal corporate entity here in the state.
Once you've found a name that's free and clear and up for grabs, go
here to download any state government forms you may be needing.
After that, you may want to familiarize yourself with our state
tax statutes,
Hawai'i General Excise Tax Law, and
Hawai'i Use Tax Law (as it may or may not apply to you).
If you need to incorporate, talk to your attorney and accountant first, then if you decide you want assistance with it, try out
Legal Zoom. They're fast, professional, and cost effective.
The Executive Corporation is also another great resource for legal forms. And
Adult Site Law has some stuff pertaining to the adult biz to round it all out.
hope that helps brah.