ailbreakMe 3.0 vs Redsn0w 0.9.7
Actually, the JailbreakMe 3.0 will be easier to perform a untethered Jailbreak iOS 4.2.1 for iPhone 4, because iPhone Dev Team member comex said you just need a slide to jailbreak your iPhone 4. But, Apple will not wait. They will do something to block the leaks. So just wish the JailbrekMe 3.0 to be release sooner. Well, the Redsn0w 0.9.7 is useful, but only with the help of iOS 4.2beta3 firmware. That means without the saved iOS 4.2beta3 firmware, you can't get a untethered Jailbreak iOS 4.2.1 for iPhone 4.