Hmm - what do you mean "use the sim card" for location finding?

Code can run on a sim card, but that's only something the carrier can do, as the code needs to be programmed onto the sim (some carriers use this to add "sim menu" stuff, for say.. checking balances, etc..)

Otherwise, if you're talking about identifying location based on the cell tower, I don't think there's any platform independent way for this, and it _probably_ varies between IOS/Android versions as well.. if it's available at all (not much use since location services, based on GPS and WiFi are around).

So err.. I guess clarification of what you want to do is what's needed for now

Cheers,
Michael

hmm... So what you're trying to achieve is an app which can track the location of the mobile phone by tracking its simcard?

I don't think that would be possible for an individuals who just simply knows how to build an app and comes up with an idea.
It's something that only the sim card carrier can pretty much do.