The one thing that really bugs me about the iPhone is that every now and then it gets hung in the wrong orientation. I have found, though, that tapping on the screen with iPhone OS 3.0 will reorient the device, no matter what is causing the hangup.
Saves a few seconds of waiting here and there.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20090611133236949