My iPhone 4 did that too. All I had was the apple logo on the screen for 4 hrs.I was sick to my stomach.
I pressed and held the home button and plugged it in to my PC and iTunes restored it ...
I'll NEVER mess with it again.. well never say never LOL![]()
Wow... 4hrs... you were much more patient than me! I was running about the place and googling like crazy within about 30 seconds