Shake to undo
How to use the shake to undo feature on the Apple iPhone
A simple but very useful tip this. When you are typing in Mail, Safari, Notes or Messaging and have messed something up just shake your iPhone.
An alert will pop up asking whether you want to Undo Typing - or remove what you have just entered.
If you do it then change your mind don't panic - just shake the phone again and you get the option to Redo Typing to bring it back again. Marvellous.