Apple brings us over 100 features in iPhone 3.0 OS. But not all features are as prominent as Copy & Paste or Voice Memo. Some features are not explicitly mentioned by Apple and you’ll have to discover by yourself. Here is one:

It’s a very simple feature and makes a very good use of iPhone built-in accelerometer. For example, you just type a sentence in Notes. You think it’s not good enough and want to start over again. In the past, you may use the backspace button to erase the sentence. Now, on iPhone 3.0, you can simply shake the iPhone and undo the typing.

After the undo, you change your mind again and want to use back the sentence. Just shake your iPhone again and it’ll let you to redo the typing.

This “Shake & Undo” feature does not only apply to Note. You can use it anywhere in iPhone such as Mail, Calendar, Messages or shuffle your music in iPod.

You can also check out another articles here and here for more tips about iPhone OS 3.0.