In a past iPhone OS update, Apple added the ability to shake the device to get an undo prompt while editing text. This still works on the iPad, but you can also access multiple undos and redos via the onscreen keyboard.
While typing text in any application, click the “.?123″ button to activate the number and punctuation keyboard. Note the new “undo” button. You can click this as many times as you want to step through multiple undos.
What if you go too far? Click the “#+=” key to activate the third level keyboard with additional symbols. The “undo” key will be replaced with “redo” when you switch to this keyboard.
Don’t forget that you can also use Command Z and Command Shift Z to undo and redo if you have an external keyboard connected.
