I was using Pandora last night just fine as well, but now when I go to it, nothing happens. Eventually the iPhone will restart and ask for my passcode again. I wonder if they're having problems with their servers.
And by the way, I'm on WiFi.
Edit: Ok, I tried it again but this time it's been stuck on the Pandora screen for 15 minutes and no matter what I press nothing happens. Is there something I can do to restart my iPhone?
Edit Again: Holding Home and Sleep at the same time worked.