This has been rehashed many many times and there are some excellent posts on the topic. You should use the search button on the top right.
Those that have done it report the following:
Without 500 hours multi crew (and it must be in a aircraft which is required to have 2 crew, PA31 doesn't cut it) it'll cost you upwards of $50K. With the multi crew time take $20K off.
Expect up to 12 months of study.
Your Aussie ATPL and IR frozen or otherwise, leave it at home. It's useless.
