Tamil Typing software for computers and mobile phones:
2. Ekalappai – One of the earliest and most used Tamil typing software. Now released as an open source software. Currently supports Tamil99, Phonetic, Typewriter, Bamini and Inscript keyboard layouts.
3. Mircrosoft Indic Language input tool – Microsoft Indic Language Input Tool helps you enter Indian language text easily into any application in Microsoft Windows or on any page on the Web. The primary input mechanism is transliteration. Additionally, it provides a visual keyboard to assist with editing words that do not transliterate properly. Supports typing in Bengali, Gujarathi, Hindi, Kannada, Malayalam, Telugu, Oriya, Punjabi and Tamil.
4. TamilKey (a) TamilVisai – Firefox extension for typing Tamil. Since it is browser based works on all operating systems but can only be used online and only inside the browser.
5. SCIM – For typing Tamil in Ubuntu.
I recommend using the Tamil99 keyboard for faster, easier, tiredness-free typing experience in the long term. You can practice Tamil99 Keyboard at http://wk.w3tamil.com
Software for typing Tamil in Android OS in mobile phones:
6. Tamil Visai – Android app for writing using transliteration, Tamil99 keyboard. Using this you can publish in Unicode font in websites. You can also send SMSes to other phones supporting Tamil display.
Warning 1: Never use Google Indic transliterator
Warning 2: You can type Tamil for free in computer. Need not buy any paid software.