According to sources , the iPhone 3GS will be launched in India on the 24th of March.
Like before the handset will come with a dataplan and will be locked to the network providing the handset for a year. In this case it still isn't clear which service providers will be offering the iPhone 3GS.
The iPhone 4G is all set to hit the US market and we still haven't gotten 3G in India barring MTNL and BSNL.
The Google Nexus One though is expected to be launched here albeit in a stripped down avatar.