Operas of Tyagaraja , Carnatic Music

There are two main operas written by the famous Carnatic music composer Tyagaraja. These are `Nowka Charitram` and `Prahlada Bhakta Vijayam`, also known as `Prahlada Bhakti Vijayam`. Know more on the performance and techniques of Operas of Tyagaraja at:
http://www.indianetzone.com/23/operas_tyagaraja.htm