RF.com’s nifty RingFree is a way that you can make VoIP calls on any iPhone, hacked or not. The currently free beta web application uses Safari and AJAX to accomplish the task. Readying your iPhone for use with RingFree is very easy to do and just involves double checking some of your settings through the standard iPhone interface.
The following VoIP service providers have been tested with RingFree:
If you don’t have a VoIP provider never fear you can also use MSN, Yahoo, Skype, GoogleTalk, FWD, SIP URI or your own PBX.
RingFree is currently a free service as they are attempting to monetize it by selling their software to VoIP service providers. Hopefully it will remain free forever.
RingFree seems to be a very nice application.
Since last year a service called spreed Connect offers a similar service. Their service offerings are high-quality call services for iPhone users worldwide. The native iPhone web application does not a software and it works with iPhones, smart phones and Web browser. The URL is: http://spreed.com/Features/connect/