The iPhone Dev Team has now released the PwnageTool 4.1 for Mac OS X, which uses the Limera1n exploit and thier original pwnage2 exploit. PwnageTool 4.1 works on a range of Apple devices running firmware 4.1
PwnageTool 4.1 works with the AppleTV 2G, iPad (firmware 3.2.2), iPod touch 4G, iPod touch 3G, iPhone4, and the iPhone 3GS.
PwnageTool allows you to restore to a custom IPSW file. For instance, you can restore to a pre-jailbroken firmware while simultaneously maintaining your current baseband (and thus your ultrasn0w carrier unlock). You can also add whatever packages you want in the “Expert” mode of PwnageTool, if you wish to pre-install Cydia packages. iPhone 3G users get the additional benefit of selecting their own boot and recovery logos, and features like multitasking and battery charge percentage.
You can find out more details about PwnageTool 4.1 and download it from the iPhone Dev Team website.