Only 2 days after the release of Fring, there is already a hack available that allows you to make free calls via the 3G network. Fring has been allowed to the App Store under condition that you can just use it to make phone calls via WiFi networks. But on the Fring forum you can already find the instructions on how to perform the hack.
» Fring hack: Free Skype calls via 3G/Edge

Many of us remember the instant messaging and VoIP application Fring from the 1.1.4 jailbreak community. Well, it’s now come to the official App Store with much of the same features, but a much more polished look. It is available as a free download in the App Store. Link to download is inside. » App Store- Fring

According to iSpazio, the developers of Fring are investigating a way to get their popular Fring (iPhone Voip application) into the App Store. He mailed with the developers and received the following answer:
» App Store - Fring soon to be released?

I received a mail from our friends within Fring with some cool news. As i posted some time ago, Fring released their API publicly, see post here. Today they are publicly announcing the first fringAdd-ons developed by fring and 3rd party developers. The first flavors of fringAdd-ons are around social networking, videos and email notifications. As you can see in the screen shots below and in the YouTube clip fring users can already get Gmail notifications, vTap videos, interact with Facebook and Orkut buddies, with more to come.
» Fring released add-ons (orkut, gmail notifier, facebook and vTap videos)

Earlier today i received a e-mail from Fring. just wanted to let you know that today we’ve opened-up the fring platform by introducing the fringAPI. We’re making it available for free, to any developer who wants to create new mobile applications or offer their own web services to the fring community. We’re very excited about this, as with the fringAPI we are adding mobile applications by welcoming in an entire world of talented developers (they only need a working knowledge of basic server-side language such as PHP, JSP, ASPX etc and XML). These mobile applications will bring users a richer experience and, potentially, an unlimited selection of mobile games, services, communities and more.
» FringAPi released for the iPhone