warpedmind: there wasn't anything really apparent about the Australian legality on erowid or any of the general resources like that, that I noticed anyway. You might have better luck in the Australian drug discussion forum, as people there are likely to know the local laws better than a group from all over the globe.
Chances are pretty good its illegal to have though, and if not, probably illegal to consume in any case.
You can get them to maturity in 3-5 years or so if you graft them onto a faster growing cactus. San pedro is popular for this... there is some fast-growing succulent that apparently works well too, though its name escapes me at the moment.