Getting to Australia from overseas cheaply and not by air?

I really thought this had been asked before but can't find such a question.

I'm looking for either a website or guidebook or detailed directions on how to arrive in Australia from another country without flying. (And also without paying some huge amount just for the privilege of doing it by surface travel.)

From time to time there's a television show or book about some adventure travellers who go around the world without flying and pass through Australia - sometimes even with a car. But amongst my many travel friends and workmates in the industry in Australia (my native country) nobody seems to really know any details on how to do it!

An answer pointing to a website or book on the topic would be perfect.

But also if you've done it yourself and tell me how that would also be a perfect answer. I assume there must be more than one way to do it but there might possibly be one central place with info on all these ways.

If you want specifics I am currently travelling around the world for as long as I can sustain it without a great deal of money. I have a return flight which cannot be extended beyond the end of May 2012 but would like to refund or forfeit the return leg if I can be reasonably sure that I'll still be able to get home at a point in the future when it may become necessary. Generally flying to Australia is a lot more expensive that flights in and between Europe, Asia, and the Americas. I would consider doing the last hop to Australia from any point in Southeast or East Asia which I assume would be the easiest, or anywhere else if this assumption is wrong.

Yes I've heard freighters might be an option but also they may be much more expensive than flights. I've also heard getting a ride on a private yacht can be done but are there some definite details I'd need to know for doing that? I've never met anybody that's actually managed to do it.