I have the same exact problem. Last time this happened, I just reformatted my phone and it started working again... but give it a few hours. At least you know it's not just you, so it's probably a problem on Apples side.
mine is not working either! Hopefully it is something they can fix soon!
imessage is not working because apple server is down due to release of IOS 6 tomorrow. will be back up later today or by tomorrow morning. just turn off imessage for now on setting so they go out as regular text messages