Follow the link provided by adamadam above - it will give you all the information you need to apply for Aus PR (requirements, process etc). Basically it comes down to a points test (check the booklet above to find out how the points test works)
You get extra points for Australian qualifications, however, they changed the rules in the last couple of years, where rather than just having a degree from an Australian institution, you have to show that you actually studied in Australia for 2 years (ie. if you are on those twinning programmes where you study in your home country and come to the affiliated Aus university for a year and then get the Aus degree, you don't get extra points)
All in all, it's a fairly easy process and if you are at the right age when applying (you get more points if you apply before you turn 30) and have the right skills and number of years experience, it's fairly easy to get still, as Aus is always looking for more skilled migrants.
No need to pay migration agents. Just apply yourself. Friend did it recently and got her PR approved. Not as easy as applying for Singapore PR, but still quite an easy process.