I have started to look into the VOIP (Voice over IP) service, well not really VOIP, well it sort of is, but it is called VoBB
Voice over Broadband (VoBB) Xnet VFX (Virtual Fone Xchange) will revolutionise the way you use your phone by merging it with your Broadband connection and putting your phone line under your control for the first time. Removing the need to have a standard telephone provider.
Using the My VFX account management portal, you now have the power to control features such as call forwarding, voice mail notification to your email at home or work, three way calling and much more....
Xnet VFX uses part of your Broadband connection as a telephone line. When you pick up the phone, or someone calls you, the call is sent via WorldxChange to your router and directly to the phone you have plugged in.
A normal household or small business currently with Broadband would look something like this:
Whereas with Xnet VFX, it would look like this (instead of the telephone line - it is using my Internet Cable Connection)

I purchased a LinkSys SPA2102 device to use as my Phone Adapter and joined the Xnet VFX service at http://xnet.co.nz/vfx/.

Basically I pay $11.00 per month NZD and for that I get a local telephone number and free local calls. National calls and calls to Australia, UK and US are 5 cents per minute, other destinations are more epensive.
I have only done a few tests with it as I still have my normal telecom connection as well. The audio quality is probably acceptable, but I would have like to have the flexability to choose a better codec. The codec that is being used is 8Kb/s so it is very lean on actual bandwidth consumed. From a simple test a one hour telephone call would not consume much more than 1 MB of data. I would be happy to double this and have the quality much higher.
This is interesting technology and I would like to see it become more flexable in regards to codecs being used.