The BA website is displaying confirmation that all passengers now have a choice to rebook, remain with or cancel current flights (with FULL refund) for tomorrow, instead of a wait and see issue.
On line booking will only work when the flight is cleared to go “open”.
The BA check flight status is working, however, i would doubt its accuracy.
I would also recommend dialing the Australian and US call centres during their office hours as it may be cheaper and quicker to get through (sign up to http://www.18185.co.uk). Out of their office hours it diverts back to London.