First off, it's good to see a fellow Kiwi

1. Make absolutely sure you have way more than enough developers freelancing for you. You can never have too many. If you think you will be able to start with 5 developers, you should get ten developers! If you ever run short and have to turn down projects you have instantly lost credibility and income.

2. Make sure they are credible, reliable professionals. There are thousands of people out there who have no idea how to act professionally. This will be your toughest part of your project, finding the right people. I would ask each freelancer to provide you with a typed (Word document) CV/Resume, examples of their work, references, then go through a professional online interview with them. You can pick up a lot from the way they answer your interview questions. Then contact AT LEAST TWO of their references. I can't stress this enough, employees (even sub contracted freelancers) are your biggest asset, and can also be your biggest liability.

3. Have your freelancers sign sub-contracting agreements for each and every project, make sure the agreement contains non-disclosure clauses, cancellation clauses, deadlines and everything required for sub-contracting.

That's all I can think of now. I don't know the demand for outsourced software development, so good luck on that one