They could be dual listed so none , but if they are say going to...

They could be dual listed so none , but if they are say going to be only nasdaq listed then the implications are currency exchange when you sell and transfer the funds back home , you need an international brokerage account , you cant trade the stock like you can here as they trade during our night. If your investment is worth more than 50K you have to declare it on your tax return each year.

I have a US based stock and an international brokerage account with commsec , they charge you over 1% brokerage on any trade , they limit how many live quotes you can have and don't give you access to market depth so you have no idea what the demand is like. Im almost certain most of the australian brokers operate like that. You can open an american based international stock quoting account to get market depth but you will need to pay a subscription fee. And transferring the shares to Nasdaq took a month or so including filling in numerous forms. I hope you get dual listing where ever it ends up being listed elsewhere.