Mobile VoIP (mVoIP) is about to become mainstream. Skype, Fring, Nimbuzz, Truphone and others are all offering mVoIP through your cellphone's Internet connection.

Classic voice over IP (VoIP) is old technology (although we waited a while for it to be legal in South Africa because Telkom couldn't work out how to monopolise it), and the next generation is poised to free users up even further by linking the technology to existing cellphone connectivity. It is global, ready-to-use, slick, good quality and, best of all, it's mostly free.

It couldn't be easier - mVoIP software allows you to talk and Instant Message (IM) via your handset's Internet connection. You will still be paying for your Internet connection, but not for a phone call. To your service provider, data is data; you could be surfing the Web, ftp-ing files to your webserver, making a VoIP call or scanning for open ports on the Pentagon's servers. It doesn't matter - it's all just data to them. So it really doesn't make a difference if you're using your Internet connection for making phone calls.

But it really makes a difference to your pocket if you make a lot of overseas phone calls.

There are many mVoIP services available, but crunchbase.com lists the popular Fring, Nimbuzz and Truphone as trailblazers. Fring is an exclusively mVOIP service that enables free mobile calling between Fring users. It is currently available through Wi-Fi, GPRS, EDGE or 3G services on Windows Mobile, Symbian and iPhone handsets. In addition to calling other Fring users, you can use Skype, GoogleTalk, MSN Messenger, SIP and Twitter to message or call for free.

Users can make calls using a non-phone Wi-Fi device if they choose. Fring has a real time contact availability feature which allows you to see who is online before you call them.

Nimbuzz is a mobile social messenger combining instant messaging, (geo) presence and VoIP across popular communities, including Skype, Windows Live Messenger, Yahoo! Messenger, ICQ, GoogleTalk, AIM and social networks including Facebook and MySpace. The free application is available on cellphone, Web and PC, for instant messaging, location sharing, (group) calling, file sharing and chat rooms. Nimbuzz has positioned itself to become a global communications platform for seamless IP-based communication among mobile devices and social media platforms.

In January, Nimbuzz was awarded the prestigious Red Herring Global 100 Award, as the first aggregated mobile instant messenger product ever.

Truphone develops mobile VoIP products for use by means of GSM/3G mobile networks and Wi-Fi/Wi-Max networks. Currently, the service is in its beta stage and offers VoIP and SMS-OIP. It has been around since mid-2006. Through the Truphone application, downloadable via an SMS message, your cellphone can make free VoIP calls and SMS texts whenever you call another Truphone user.

Version 3.0 (the latest) offers "presence" detection, which alerts you when you can make free calls.

There are other mVoIP providers, such as barablu and jajah, but just as Skype became the dominant VoIP platform, one or two of these newbies will also stand the test of time, making the joy of truly seamless IP connectivity another good reason for SA's data service providers to charge even more than the outrageous cost per meg that they're already squeezing out of us.