A while back I uploaded

this video of my sister's dog growling. I only uploaded the video because the yorkie blew a snot bubble. Some people say that it looks like the dog is smiling. Well an creditable world wide advertiser with an office in Australia saw the footage and wanted to buy the rights to the footage to possibly use it in a dog food commercial.

They sent me a general release contract. In the release it states that they will pay me "US$1,000.00 (excluding GST)." So I find out that GST in Australia is Goods and Services Tax, whatever that % may be. Am I correct that assume that they will withhold the necessary taxes on their side so I should expect less than US$1,000?

Later, am I required to file an Australia tax return and maybe pay more or get a refund later? Do we have tax treaties with the Commonwealth of Australia where they will report this earnings to the IRS, when then I would have to report it? I have no problems taking a gamble that they won't report and chance that I don't get audited for 2008.