Hey I have finished my cert II exam through tafe, I did it for my HSC. I have also been doing Cert III through OTEN using Thompson Education Direct. Some of the units are pretty hard, im halfway through the course, the first like 4-5 assignments suck so bad it like OH & S and customer support, really boring, but as soon as you get into the mathematic stuff its really fun!
Good luck juyoung, hope you enjoy.
BTW Thompson Education Direct has a really good forum, they have tutors that answer any questions you have, and its a really good comunity