I have a 3GS.
I was taking my son to his girlfriends and had my GPS (Tom Tom) app on and went to access iTunes. It said my library was empty. I then attempted a reset. It then got stuck at the Apple logo. The only way to turn it off was to hold down the Sleep/Wake button and the Home button. Restarting it just brought it back to the Apple screen.
I plugged it into my computer with iTunes running. The phone turned on but stopped at the Apple logo...for about 10 minutes. It finally rebooted and is syncing right now. My battery is showing it's 68%.
Anybody have any idea what is going on? I'm heading out of town on business for a couple of days on Sunday evening and am relying on the iPhone for the trip (phone, internet, GPS, and recording interviews). I'm a bit concerned right now.