My iPhone arrived today, imported from the USA, unlocked and absolutely amazing

I love it.
Obviously, it came with those funny american power prongs, so I swapped it out with the equally-amusing Australian duckhead prongs I had laying around from my MacBook Pro power attachment.
Before I use it though, it there going to be any problems charging the iPhone from the wall socket in Australia? I know the voltages are different, but I'm no expert at how it all works.
I'd hate to fry it is all.