I hate it turn the screen sideway when I lay in bed to browse web and check my email. Do you have the same problem?
With the release of iOS 4, Apple has finally introduced a screen orientation lock for iPhone. To lock your iPhone to portrait orientation,
1. You can simply tap the HOME button twice to bring the multitasking dock.
2. Swipe your finger to the right until you see the music control buttons.
3. Then just tap on the lock button. After you enable the screen lock, the auto rotation is disabled and your screen is locked to the portrait orientation.
To re-enable the auto rotation, you can simply go through the steps again to turn off the lock.