Rockstar have issued a press release stating their position on the crazy censorship restrictions for video games in Australia.
[i]The Australian version of Grand Theft Auto IV was rated by the OFLC in December 2007 as MA15+. Unlike the US and Europe, Australia still lacks an R18+ rating for video games and as a result many games are edited for release in Australia, including most previous Grand Theft Auto releases.
While there are some minor differences between the Australian and US/EU versions, they are not significant and we do not believe they take away from the level of scope and detail that make GTA IV such an incredible experience. We would not release the game in Australia if we believed these differences compromised the quality of the game in any way.
We strongly support the OLFC and will continue to work within their guidelines; however we believe the government needs to bring games in line with other media by introducing an R18+ rating, or edits to games will continue to be necessary. We encourage consumers to let their politicians know that they support an R18+ rating for games.
So what exactly has been cut from the final release? Rockstar isn't commenting. But good on them for stating their position clearly and appealing for change.