Adult Swim has a free app that lets you stream full episodes of all your favourite shows (and various clips!). There's also a TV schedule, a dashboard to get all their games (that you have to pay to play) and the iPad version even throws in a music player, a clock, weather and a calculator. Why? Who knows!
[Just checked this and while it isn't available on the Australian App Store, if you can get it from the US Store the app works. Can't tell if some things are missing, but there is a good collection of both full episodes and clips to choose from. -ed]