The applications below may do more than just allow you to voice chat—many also allow you to call telephone numbers or video chat. We are evaluating these apps based on their user friendliness and quality of audio. On to our contenders!
The only exclusively mobile app on our list, Fring is a cross-platform app that allows you to call other Fring users and outbound telephone service via FringOut. It also has plugins for many other platforms including Google Talk and Skype. One of the more interesting applications I see with Fring is SIP compatibility, which allows you to interconnect with many other phone services for cheap calling rates, or to use it as an office extension.
The Google Voice service (via Google Talk) is another excellent voice chatting service. Google launched their voice service in 2009 after purchasing GrandCentral. After integrating it with the existing Google service, Google then offered free chat service (between Google Talk users) and also to regular phone numbers through Google Voice. It is easy to access through your web browser, and you simply dial the number you wish to call. You can also request an inbound number to forward to a number of your other voice chat devices.
Muble is an open source voice chat application that is geared towards gamers and is optimized for low latency. Once you and your friends are in-game, Mumble interacts with the game to provide positional audio – meaning that it will make it sound like your friends voice is coming from a specific direction. You must have a server for each Mumble client to connect to.
Skype is one of the oldest voice chat apps, having started in 2003. Fast forward to today, Skype now has about 18 million people online at any moment in time. The basic Skype features are free – you can call to any other user with both voice and video for free. If you pay for it you can also buy Skype credits which allow you to call internationally for a minimum fee. Skype continually adds new features to their product.
Another application that is geared towards gamers, Ventrilo is a low-latency and efficient voice chat application. It is very lightweight and runs in the background. Ventrilo uses a client-server architecture and you can either run one on your own connection or rent one – many game hosting providers also provide a Ventrilo server.