As a general comment for any company if you are billing in USD and converting back to AUD when the USD is weak and the AUD is strong - then thats going to hurt earnings on the currency conversion.
In terms of NMS the US component of earnings was 13% in FY08. 76% of earnings from Australia, 8% from UK and 3% from SE Asia.
Assuming the earnings mix hasnt changed much then I wouldnt think currency would impact too much.