The main classical dance forms in India are Bharatnatyam (from Tamil Nadu), Kathak (from North India), Kuchipudi (from Andhra Pradesh), Kathakali (from Kerala), Odissi (from Orissa) and Manipuri (from North-East India).

The name is said to be derived from Bharat Muni, the author of Natya Shastra (an encyclopedia on Dance, Drama and Music). Some also say that the name is derived from the syllables Bha, Ra, Ta, which stand respectively for Bhava (expressions), Raga (Music) and Taal (Rhythm).

In a dance performance there might be several items which would include the Allaripu, Jatiswaram, Shabdam, Varnam, Tillana and some Padams.

Following are some articles on Bharatnatyam:

http://www.geocities.com/Tokyo/Shrine/3155/bnatyam.html

http://in.geocities.com/medhahari/bharata_natyam/bharata_natyam.html