You can lock orientation in iPad easily. But there is no button for orientation lock for iPhone and iPodTouch. However, we wanna lock orientation sometime. If you are using iOS 4.0 or higher , you can do it. Double click the home button and Multitask bar will appear. Scroll to the left and you will see iPod control and orientation button (the first left button).
You will see lock button at the status bar.
If you want to unlock, click lock button again
