Acronym for VoiceOverIP
http://www.zultys.co.nz/LIPZ4.htm
http://www.zultys.com/products/lipz4/softphone-1.3.11-0.i386.rpm
http://www.xten.com/index.php?menu=products&smenu=xlite
This is a very powerful PBX software designed so you can build your own mini-exchange like in use in large companies. it scales very well and is extremely powerful. It has support for all sorts of protocols and lets you dial internal or external users and trunk calls in various ways.
FreeWorldDialup? (FWD) http://www.pulver.com/fwd/
Sipphone.com http://www.sipphone.com
Clients can be connected to more than one service at a time, think of it as having 2 seperate phone lines, both connected to different providers but both phones plugging into one unit.. so feel free to sign up for accounts at more than one service.. you can select which service you want when dialling away from the default service by starting to dial your numbers with #2 for the second account you have setup etc.
SIP is the new protocol used to initiate communication between various units, and it is a standard met by clients on linux, windows, or on stand-alone voip phones. This means you can call any user on the network not caring what kind of hardware they are using, the SIP should help start a common conversation so you can talk to each other.
23 pages link to VoIP:
