International Keyboards
1. How to install and switch keyboards
The steps are similar on both platforms: 
1.1. On the PC (Windows XP) go to the “control panel” section and choose “regional and languages options”.  Select “languages” then “details” and follow the onscreen instructions to add the new languages (for earlier versions please refer to their manuals).  Once added, you can switch between keyboards through the language bar that appears on the desktop or through a key sequence.
1.2. On the Mac (MacOsX), go to “system preferences” and select “international”.  Then choose “input menu” and checkmark the languages you want to add. Once added, you can switch between keyboards through the language palette which appears on the desktop’s menu bar or through a key sequence.

2. How to install Greek Polytonic
You may add Greek Polytonic to the system by following similar steps as for other languages: 
2.1. On the PC (Windows XP), go to the “control panel” section and choose “regional and languages options”.  Select “languages” then “details”. Press the key in the “settings/installed services” section and choose “Greek”  from the “input languages” list. Finally choose “Greek Polytonic” from the “keybord layout/IME” list. Greek/Greek Polytonic is now installed (for earlier or later versions please refer to their manuals).  Once added, you can switch between keyboards through the language bar that appears on the desktop or through a key sequence .
2.2. On the Mac (MacOsX), go to “system preferences” and select “international”.  Then choose “input menu” and checkmark “Greek Polytonic” (MacOsX 10.4 Tiger and later). Please note that earlier versions do not include Greek Polytonic so you have to buy an extension locally). Once added, you can switch between keyboards through the language palette which appears on the desktop’s menu bar or through a key sequence.