There are three ways to place a VoIP call. You can buy an analog telephone adapter (ATA), buy an IP phone, or talk directly from one computer to another.
An ATA is a simple way to start using VoIP. You take the adapter out of the box, plug it in and you're ready to make VoIP calls.
If you want to get a little fancier, you can buy an IP phone. It looks like a regular phone but has all the software you need to make IP calls. When Wi-Fi phones become available, you'll be able to make IP calls from any Wi-Fi hotspot.
Talking computer to computer is the easiest way to use VoIP. You can get the necessary software free or at very low cost. All you pay is your normal ISP (Internet service provider) fee.