Not only do users enjoy unlimited mobile calls between other users when connected to the Internet they can also have low rates for calling any fixed-line or moblie phone. With SIP-enabled phones, that have WiFi capabilities, MediaRing lets users also keep existing mobile phone numbers.

Sounds like the best of two worlds: mobility and choice to spend money wisely, all with seemless connectivity through an already existing phonebook. Think this is a huge cost? MediaRing says their rates for international calls start at 2 pennies a minute (sounds about the same as others).

I wonder as the success of this type of service is always dependent on an available wifi connection. I guess if we spen most of our time at home, work, or a coffee shop it'll work just fine.