"Activation Required" ?

Right, so when I went to bed lst night, everything was fine. I woke up to my phone turning on and sayinf "Activation Required", when I got to unlock it, it simply tells me to plug it inot iTunes, simple enough right? I plug it into iTunes, iTunes takes a couple seconds to detect it, then sites there for a about a minute not letting me do anything.

Oh, and my phone restarts after being on for only, on average, 1 minute and 20 seconds.