Blackra1n for Mac OS X users has been released and is available for download. Few days back Geohot released Blakra1n Windows version. Mac OS X users can now jailbreak iPhone OS 3.1.2 firmware (both for iPhone & iPod Touch). With Blackra1n you can also jailbreak iPod Touch 3 (ipt3), but the ipt3 is tethered. It is important to note that blackra1n doesn’t hacktivate your iPhone which means that if you are not on an official Apple approved carrier BlackRa1n cannot activate it.
Warning – iPhone and iPod Touch users with unlocked iPhone 3G and iPhone 3GS, should not upgrade to iPhone OS 3.1.2 using iTunes as they will lose unlock because baseband cannot be downgraded. Instead use Pwnagetool 3.1.4 if you care for unlock without updating baseband.