I recently came across a couple of really useful sites for downloading vector latlong boundary data for free
converts entered address into lat/long coordinates (has a batch mode): http://stevemorse.org/jcal/latlonbatch.html?direction=forward
Tool that lets you enter a lat/long coordinate, and then get vector data for the administrative regions that point is in....has an API http://global.mapit.mysociety.org/
The source of the data in the last link is OpenStreetMap, and these tools together have been great for getting lat/long boundary data of the districts within India's states. However, I'm wondering if the same boundary data exists for India's telecom circles, similar to a map of US area codes.