I think the share trading platforms on any of the big 4 banks...

I think the share trading platforms on any of the big 4 banks offer international. So if you talk to your bank they should be able to set you up. Just check that they support the W8BEN form. When you complete this form the withholding tax on dividends will go from 30% to 15%. The 15% withholding can can be offset against your tax liability to the ATO. In the mygov tax portal there is an international income option. It really isn't much harder than domestic securities, except you will have to convert from USD back to AUD in your calculations for dividends and CGT.

One other point to watch is the spread (gap between midpoint and actual exchange rate) when converting AUD to USD. I think 50 basis points is pretty good. Some of the 'cheap' brokers have a larger spread of 2% or more. If you are trading small amounts, say 5K or less the cheaper broker with the higher spread makes sense. If you are trading larger amounts like 30K, then the spread between AUD and USD becomes vital. 25K to 30K is a magic amount for trading because the cost per unit doesn't go down after this on most platforms.

You may wish to look at interactive brokers (IB). I have heard great things about it and to my understanding it is one of the best cut price brokers. The reasons I use my bank is because of convenience and the fact that ASX securities will be held in your name instead of the brokers account name (on the CHESS system - or whatever ASX is moving to next). For small portfolios, say less than 100K, I would definitely look at IB or possibly CMC markets, though the feedback for CMC isn't as good.

Apologies to CSL holders for the diversion.