Hi Scott,
I'm from Vermont originally, but moved to Wellington from Seattle back in 2005. I have Permanent Residency through the Skilled Migrant Category.
If you are under thirty, the least complicated way to proceed is to get a work visa for those under thirty. Otherwise, checked out the Skilled Migrant stuff.
You should go to that site and do the points calculator. It's under the Expression of Interest stuff here:
This should give you a decent gauge of where you stand. If you have enough points already, immigration can be a very smooth process and go fairly quickly. Basically immigration needs to have confidence that you walk out of the office and get a job based on your work experience and qualifications. They obviously don't want to approves someone that is just going to end up being a cost to the government.
If you have high enough points and get approved without any hitches, you can collect your stuff in your passport and do what you wish to make a living, including contracting.
However, for me because I was on edge points wise, the trick was to actually get my points up to finalize my application was to get a job here. From my experience, that is best done by coming over and visiting and interviewing in person. Once I did that (was pretty quick once I actually started applying, but that was well before the recession), I was on "section 18A" for a like a year or something which meant that if I didn't stay employed they could revoke my permit and visa, etc.
After my 18A probationary period finished, I was free to what I wanted as far as employment. I'm pretty happy with my job, so I stayed on, but I could have set up shop as a freelancer.
Definitely don't mention that you are planning on being self-employed in either case. That will throw up red flags for immigration.
I love it here. Has some of the best aspects of bigger cities while having a very friendly smallness, too.
All this boils down to that I recommend you plan to come here for your job hunt. Worst case scenario is that you end up having visited a very cool place.
Cheers,
Walter