Not in the US yet, but be prepared!!! If airport security asks you to show them your cell phone works, dont get upset with them!!! They have good reason. The following video shows what has been discovered in foreign countries, and has completely changed their airport security measures. Dont hate the security personel!!! They may be doing you a favor.
What they found was, well, eye opening to say the least. Apparently, the "bad guys" figured out a way to cleverly disguise a 4 shot 22 pistol in the form of a cell phone, and can be "activated" by use of the keypad. Have a look-