Australian resident. Have opened an account, as a corporation with ThinkOrSwim in 2003. No problems. Took about 1 weeks. Some time ago though.
Opened an account, as a corporation with Interactive Brokers about a month ago. No problems. Took about 2 weeks. Admin staff seem not so bright. Worked out ok in the end.
Also, here's the problem with these two brokers IMO:
ThinkOrSwim -- Great charts. Did have great tools, esp tick database. No more. Expensive commissions compared to peers. Gradually being "porked" by Ameritrade, which took them over recently.
Interactive Brokers -- Terrible interface, and the "API" is a bit of a mickey mouse job. The damn thing needs to reset itself once per 24 hours [!!]. POS for program trading. The "tick data" is NOT ticks. No way. Nah ha. Fun for a retail trader to play with a "program trading API", but oh boy .. low frequency strategies only.
*** Cannot beat their commission rates, and world exchange access however.
Summary: Execute trades through IB. Buy a data feed from someone else. TOS is a good intro mix of both.
Also, for the newbees -- Trading is easy. Trading profitably is very hard. If setting up an account is getting you down, probably best to stop now, and just buy a datafeed to paper trade against.