Christmas may be a time for giving, but if Optus were Santa Claus, the entire holiday season would suck worse than the Star Wars Christmas Special. This year as a.gift to its 'yes' Timeless and capped plan customers, Optus sent a special Christmas Eve SMS message announcing that they would be charging international calling rates for calls made to Australian GSM numbers that diverted to international calls using VoIP. As a backgrounder, there are several services that allow you to call a local Australian mobile number, who then divert your calls over the internet to an overseas location, meaning you can make international calls cheaply from your mobile. As APC points out in their extensive coverage of the issue, the problem with Optus charging International rates for these calls is that they don't actually carry the call to an overseas destination, and therefore don't incur any fees - all they do is send the call to an Australian number. In other words, this is greed, pure and simple.
APC also suggests a course of action to people affected by Optus' move - first, send the network a formal complaint, then contact the ACCC, the Office of Fair Trading or the telecommunications industry ombudsman to make your complaint. If enough people make enough noise, hopefully next Christmas won't see the same horrible gift sent to Optus customers again.