Right on cue, Apple has rushed out the new iOS 6.1.1 firmware update to the iPhone 4S owners to fix 3G connectivity issues, enterprise problems and quite possibly squash a few reliability related bugs. iPhone 4S owners can apply an over-the-air update by going to Settings > General > Software Update. Of course, if you're already jailbroken, do not update to iOS 6.1.1 until it becomes clear whether or not it breaks the jailbreak...
Apple posts iOS 6.1.1 firmware fixing iPhone 4S reliability, 3G issues