Install only if you can read தமிழ் மொழி இனியது.
If you see BOXES your device does NOT support Tamil.

Steps

1. Goto Settings -> Language and Keyboards

2. Enable Just Tamil

3. Select Input method -> then JustTamil

Works only if
1. Tamil Font Installed
2. Device Complex Font Rendering.

Latest Indian firmwares supports these.
All Device above 4.0 Ice cream Sand-witch.

Report any issues or requests here or mail to [email protected]