BSNL has launched an unlimited 3G plan for pre-paid and post-paid customers in Chennai. This offers speed up to 3.6 Mbps till 5GB, and after that speed would be throttled to 100 Kbps. They offered 3G unlimited iPad plans few months back but stopped it suddenly. This is not a lot but you get unlimited usage even after the 3G data limit.
BSNL 3G unlimited data plans
This is a promotional offer that is valid from 04-01-2012 to 02-04-2012 for pre-paid customers and from 10-01-2012 to 08-04-2012 for post-paid customers . This is available for Existing and New BSNL 3G customers in Chennai. This cannot be clubbed with any other Data RCV and 3G NIGHT accounts.