Siphon offers free calls on iPhones

Software has surfaced for Apple's iPhone and iPod touch (with an accessory microphone) that allows users to make free phone calls to other users. The application, titled 'Siphon,' requires an unlocked iPhone and connects users to the freephonie network. iPhone owners or iPod touch owners with microphones must activate SIP functionality and enter a username/password combination to authenticate with the network.

An online guide offers detailed installation instructions of Siphon, and walks readers through the setup process. The company says the service will be extended to all iPhone and iPod touch owners independently of their operating, and is subject to availability of the SIP service.