The iPhone 4S has been officially jailbroken. According to a report from iClarified the iPhone Dev-Team demonstrated a "VERY preliminary" way to get Cydia running on both the iPhone 4S and the iPad 2.
There are still big pieces missing and plenty of work left to do, so unfortunately the jailbreak won't be released to the public. Luckily, we can at least get a peek from this video.
"Cydia lets users browse and install unofficial apps on their iDevice. MuscelNerd, the lead developer of the iPhone Dev-Team, says this is a userland exploit that occurs after iBoot is out of the picture."
According to MuscleNerd, this is a userland exploit that occurs after iBoot is out of the picture.
Here's a short video of current JB working on iPad2: