If you want to trade US market set up account with US broker....

If you want to trade US market set up account with US broker. $50 commission here vs $4.99 commission there is a huge difference. Normal commission there is $9.99 but from experience you can haggle them down to at least $5. I know people who pay $3 per trade with Lightspeed Trading.

To set up US account you will need (a) US address/telephone no (K7net) and (b) US taxpayer ID number with the IRS which is their ATO. Once you get a tax ID you're 99% done.