The iPhone 4 doesn't just have an antenna problem, there are also issues with the proximity sensor and Apple will address those in the next iOS 4 update. For now, there are some unofficial fixes you can try.
Apple has released iOS 4.1 for the iPhone and iPod touch and it promises to do a bunch of things including fix the iPhone 4 proximity issues and improve the iPhone 3G's speed.
GTXO Stock News : GTX Corp and BrickHouse Security Team to protect the 2,000 children reported missing daily with GPS personal location solutions. New iPhone utility App - Code Mobile - from GTX Corp, together with the BrickHouse Child Locator, use the most advanced GPS PLS proximity alert technology to provide protection for children locally and nationally
During Apple's Fall event, Steve Jobs announced that iOS 4.1 will be coming out next week and it will be fixing a bunch of bugs and adding Game Center and HDR photos. \n
Home Zone monitors Airport networks and Bluetooth devices in your
proximity and can automatically trigger user-definable actions when
configured networks or devices appear or disappear.
Pressure switches MCS have two adjustable switching points (On and Off). The contact system switches when they are attained. This can be used either as a signal for actuation of an auxiliary circuit (contactor control system, PLC) or for direct switching of a load.