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http://www.google.com/ime/transliteration/help.html#installation

Google Input Method: Type anywhere in your language

Smart, easy to use and intuitive!

            Choose your IME language              Amharic            Arabic            Bengali            Farsi (Persian)            Greek            Gujarati            Hebrew            Hindi            Kannada            Malayalam            Marathi            Nepali            Oriya            Punjabi            Russian            Sanskrit            Serbian            Sinhalese            Tamil            Telugu            Tigrinya            Urdu          
 32 Bit  64 Bit 

Download Google IME

Requires Windows 7/Vista/XP (32-bit/64-bit)
Installation Instructions

Google Transliteration IME is an input method editor which allows users to enter text in one of the supported languages using a roman keyboard. Users can type a word the way it sounds using Latin characters and Google Transliteration IME will convert the word to its native script. Note that this is not the same as translation -- it is the sound of the words that is converted from one alphabet to the other, not their meaning. Converted content will always be in Unicode.

Google Transliteration IME is currently available for 22 different languages -Amharic, Arabic, Bengali, Farsi (Persian), Greek, Gujarati, Hebrew, Hindi, Kannada, Malayalam, Marathi, Nepali, Oriya, Punjabi, Russian, Sanskrit, Serbian, Sinhalese, Tamil, Telugu, Tigrinya and Urdu.