Apple has released a third public beta of iOS 5.1 to developers. It’s available for download from developer.apple.com if you have a developer account.
For the most part this is a bug fix release which doesn’t offer any major new features, but it does return the option to disable 3G and rely on Edge wireless connectivity which can help prolong your battery life (while slowing your internet connection to a crawl).
The update changes the baseband, so if you jailbreak and carrier unlock your iPhone, you should probably proceed with extreme caution before applying the latest update.
