well there are 2 theathres (major ones) in chennai that have started with online booking of current shows and online booking of future shows.one is chennai's largest satyam cinemas. their online booking site is
https://www.thecinema.insecond is abiram theatres in purasaiwalkam which also has booking through interernet and smsfor abirami's tickets and tickets from few other theatres u can check out
www.sulekha.com