Ab bus!
One more website offers bus tickets online

Rediff.com has launched their Bus FareSearch service (http://www.bus-tickets.rediff.com/index.php).  It allows the users to search for buses plying between states and get detailed schedules, pick up points, check availability and book seats for over 1000 destinations in India. The new search service currently covers over 20000 buses including both private and state transport buses for 7 Indian states - Maharashtra, Karnataka, Andhra Pradesh, Rajasthan, Himachal Pradesh, West Bengal and Uttar Pradesh.
 The Rediff Bus FareSearch service also allows users to get comparative view of the trains available for the chosen bus route helping users to plan their travel more efficiently. 
Once the user has finalized the appropriate bus they can book the tickets either through travel agents whose details are also available on the system and also through partner sites.