iPhone OS hacker, GeoHot, released an updated version of Blackra1n earlier this week, a jailbreak utility for iPhone OS 3.1.2 and iPhone baseband 05.11.07 that now includes a carrier unlock that lets you use the iPhone on any GSM carrier.
We covered the initial release of Blackra1n that was Windows only, but now a Mac version of Blackra1n is available. Mac users can use Blackra1n to jailbreak or unlock all iPhone and iPod Touch models regardless of its hardware generation.
Using the application is simple. You just connect the iPhone or iPod Touch using the standard USB sync cable to a computer and follow iClarified's tutorials on how to jailbreak and unlock your iPhone 3G, 3GS using BlackSn0w for Windows or Mac.
Note: By jailbreaking or unlocking an iPhone or iPod Touch, you may be violating your terms of service agreement and voiding your warranty. CNET does not recommend jailbreaking or unlocking; proceed at your own risk.