The jailbreaking solution for iPhone 3.0 firmware in the new iPhone 3GS, purplera1n (for windows) which was released for windows, is now finally available for mac users too. It has the same functionality to what a windows user saw to jailbreak the new firmware.
As you already know, its GeoHot a team that has released the tool to jailbreak iPhone 3GS, and iPhone dev team has not yet released officially any app for the same purpose. There have been errors reported, so better backup your iPhone data before you jailbreak it.
How to Jailbreak the iPhone 3GS in Mac using purplera1n –
Download and unzip the file, open purplera1n
Install iTunes 8.2 if you haven’t already
Connect the iPhone
Click on Make it ra1n in the purplera1n app
It will start the process of jailbreak for you
Then you see a Freeze app in the iPhone, open it. It will help you download Cydia and when Cydia downloads and installs, you are free to add any 3rd party apps like ultrasn0w to unlock the phone too.
And you would also be instructed the steps while you are performing them.
To jailbreak the iPhone 3.0 OS, there is a redsn0w and pwnagetool 3.01 version released by iPhone dev team, but purplera1n helps in jailbreaking the iPhone 3GS mobile phone with 3.0 firmware in it.