Voice over IP calls have come to the iPhone, thanks to London's Fring which released a beta version of its VoIP software for the iPhone yesterday.

The release of the first ever functional VoIP solution marks a watershed moment for iPhone development - albeit unauthorised iPhone development; this software only functions on a jailbroken iPhone.

Initial reports from those who have used the software indicate that fring works well on the iPhone, with Computerworld reporting: "I just made my first Skype call on my iPhone (over WiFi).  It sounded great."

"This special pre-release version of fring, developed in conjunction with the Israel-based Holon Institute of Technology academic research labs is a direct response to iPhone users kicking our behind to get fring for their devices," the developers explain.

The developers want user feedback to help them improve the software while they develop a fully-featured version of the software for the device, though it isn't yet known if they plan to follow Apple's rules in the release.

Fring lets users communicate with contacts from AIM, Google Talk, ICQ, MSN, Skype, Twitter, and Yahoo lists. Users can make calls or send instant messages over WiFi. Fring also works with more than 500 mobile handsets

Fring also offers iChat-style presence indicators to display status and is available for free download.