Apple just pushed the iOS SDK 4.1 beta to developers. This move is widely expected to NOT fix the antenna issue but rather hide it behind cosmetic changes. This beta version (for developers only) will show bigger bars and will fix the formula that calculates how many bars are displayed, which Apple said to be “totally wrong“.
Unless you’re a developer, you really have no business playing with the iOS SDK 4.1. beta. Also keep in mind that installing this beta version or the future official iOS 4.1 may compromise your chances of jailbreaking or unlocking your iPhone.