Here's the best website I've found for advice:
http://britishexpats.com/forum/forumdisplay.php?f=54
There's a link on the left for the immigration section, and there's lot several sections for general chit chat about Australia.
The website is aimed at people from the
UK but there are people from all over using that site. We did our visa application ourselves and I learned everything I needed from that site.
Now. about your visa chances.
First off you'll need to decide who the main applicant will be. It looks like you're boyfriend is probably the only option. The next step is that he needs a job on the Skilled Occupation List (SOL) which I suspect he will have. Then he will need to have some recent work experience in his occupation, which I believe is at least 1 year in the last 18 months before you apply. So it looks like you'll be waiting at least a year to apply for the visa. Once he's got the work experience then he'll have to apply for a skills assessment. The skills assessment may require more work experience than the visa so it's best to look into that now. Once you have a positive skills assessment then you can apply for the visa, you MUST have this for the visa application.
Next problem is getting the points. If your boyfriend has the full 120 points on his own then it doesn't matter what you do. However, if you're short 5 points then you'd need to be the secondary applicant. Which means you'd also have to have a jobs on the SOL, skills assessment and recent work experience. But, like I said, if your boyfriend has enough points on his own then it doesn't matter.
The last thing I should mention is that to go as his "defacto" girlfriend then you need to have been together for at least a year. You would have to provide documentation of your relationship like shared housing bills, bank statements and proof your relationship is genuine (photos, statements, events attended together, etc). So if you haven't got any of that then I'd start making sure you can provide it when the time comes.
If everything else fails you could always try the
working holiday visa (WHV). You'd only be allowed to work in
Australia for up to a year. Also, you only qualify if you're under 30 and not married. But, it could give you the chance to come over and find sponsorship for your boyfriend. It would be a difficult route though with no guarantees.
Good luck with your plans.