Have you got a German keyboard and find you sometimes have to type a £ or ¥ sign?
If you are using Word or Outlook, you can always click on 'Insert', then the menu point 'Symbol' and scroll through all the characters there until you come to the one you need or you can use ASCII code (an acronym for the American Standard Code for Information Interchange) which is often much faster if you have to use a special symbol frequently. If you want to use the pound sign, for example, hold down the Alt key and press 156 (or 0163) and, hey presto, the pound symbol should appear: £
You can also assign your own shortcut key to a specific symbol, e.g. Alt + P for the pound symbol. I use Word 2003 and the screen to do that is found under 'Insert' ---> 'Symbol'
Select the symbol you want to create a shortkey for, click on the 'Shortcut Key...' button at the bottom of the screen and then assign a combination of keys to generate the symbol automatically in future. NB.
Do not use a combination of keys that have already been assigned as shortcut keys, e.g. Ctrl + Y (which is normally used to redo or repeat an action).