A list of Free Tamil fontsdownload websites. These will help you to read and write Tamil in various encodings like Unicode, Bamini etc., in Microsoft Windows, Linux, MS Word and Adobe products :
1. Technology development for Indian Languages (TDIL) is a Government of India initiative under Indian Language Data center (ILDC). ILDC provides Open type and True Type Tamil fonts for download from Centre for Development of Advanced computing (C-DAC), Chennai Kavigal, Cadgraf Digitals Pvt. Ltd., Modular Infotech Pvt. Ltd., Pune.
2. Tamil Wikipedia Font Help page gives detailed instructions on how to install Tamil fonts across all operating systems.