Apple's invited developers to build, test and compile their apps with the iOS 4.2 GM seed for approval. This could mean that iOS 4.2 has moved past beta and will be available in retail soon.
Screenshot of the request for iOS 4.2 Apps on the Apple Developer's Site
iOS 4.2 will make multitasking and folders possible on the iPad. It also incorporates an orientation lock for the iPhone, iPod Touch and iPad. This will mean that the iPad will lose its orientation lock toggle on its hardware but this will be used to mute audio. iOS 4.2 will also bring Game Center to the iPad.
So if you're a developer, go to the Apple developer website, log in and go wild.