Yes it is very much possible. What are you trying to do exactly? Are you trying to do create a wordpress blog? like www.tamiljamuna.wordpress.com Or Trying to put a tamil website like tamiljamuna.com & install wordpress in your hosting account? Or trying to implement tamil interface in wordpress blog / cms?
Are you using your own domain with hosting or using "something.wordpress.com". See the following links for help. http://www.monusoft.com/Products/WordPressPlugin.aspx http://ravidreams.com/forum/topic/tamil-version-of-wordpress http://groups.google.com/group/tamil_wordpress_translation/browse_thread/thread/b10928a25f6c310e http://wordpress.org/extend/plugins/indic-ime/ http://oorodi.com/tag/தமிழ்-வேர்ட்பிரஸ்