Hide tethering from carrier iphone
It's a bit ridiculous that carriers charge for data and then charge an extra fee sometimes for you to use that same data for tethering. Don't you think? Here...
But there are many apps — particularly on Android — that promise to hide tethering activity from wireless carriers, making it hard to distinguish what data is actually being used for.The contract will almost certainly state that service can be withdrawn at any time on their sole discretion for any suspected breaches; if you're tethering on a contract that doesn't allow it, they're well within their rights (which you've agreed to by accepting the contract) to block your service until you comply or close your account completely.
Tethering doesn't officially work in iPhone 3.0 for AT&T customers, but for Mac users there's an easy tweak to enable the feature in seconds. Here are the steps, courtesy of MacMegasite.