The Royal Institute for Deaf and Blind Children have had an AUSLAN iPhone app available for a while now, but it costs $50. So yesterday they launched a free app for both iPhone and iPad that will teach iOS users 150 key signs, so they can learn the basics of communicating with sign language.
As well as offering short video clips of how to say 150 key words in sign language, there's also the alphabet and numbers, which should offer enough to communicate with anyone. The app's been launched to celebrate the Institute's 150th anniversary here in Australia.
Considering it's free, and practically useful, you should go and download it right now.