Earlier Vodafone announced its plans to bring iPhone4 to India and though further details aren’t yet announced, Airtel is planning to bring iPhone4 to India by September/October timeframe (source).
While 3G services takes their own sweet time for implementation, don’t you think iPhone 3GS route is more viable than iPhone4?
Airtel has been promoting iPhone 3GS with an introductory offer of free 500MB worth of data transfer for the first year, though uptake is yet to be seen.

How much are you willing to pay for iPhone4, that too with an antenna problem?
Recommended Read: Are Smartphone Users Really Smart? Note to Nokia Fanboys
PiToon:Spotted : Steve Jobs and Bill Gates talking about iPhone 4