VoIP has been ushered onto the iPhone in quite a few incarnations, but we'd wager than none of 'em are as useful as iCall. Said application is currently in beta form, though a release isn't quite ready for the public at large. Put simply, it enables iPhones to switch from GSM to WiFi (when WiFi is nearby, of course) on-the-fly in order to save cell minutes and bypass the hassle of manually changing over. Interested? We thought you'd be -- hop on past the break to see a demonstrative video of the app in action, and keep a close eye on the read link for a sure-to-surface-soon download.