Seems the new Apple iPhone 4 has a major flaw.. The metal chassis acts as the antenna and holding it the "wrong way" reduces the signal, killing off any 3G connections.
BBC Story Here
The worst thing about it is the official line from Apple, "
avoid gripping it in the lower left corner in a way that covers both sides of the black strip in the metal band". Otherwise translated as "Ooops, we messed up there".
So glad I got my HTC Desire a few weeks ago..