Free calling from one PC to another on the Internet has been around for quite some time, but now you can make calls to standard telephones for free.
PC to PC calling has its share of drawbacks. The person you are calling not only needs to be online they need to be running the same Internet phone software you are. The sound quality of your call is dependent on your connection speed and the other person's connection speed. If the connection is slow or there is a lot of traffic at just one end it may be impossible to hold a conversation.
On the other hand when you use services that allow you to initiate your call from your PC but call standard telephones you are the only one that needs a special setup. Typically your connection will be the only limiting factor since the service provider will be using high speed connections at their end.
I'm not saying that you will always have high quality audio, but your chances are better, particularly if you have a cable or DSL connection or if your dialup ISP has plenty of capacity and a good connection to the Internet itself.
Initially most of the services only offer calls to the US but they claim to have plans to offer calls outside the US. If you live outside the US you can still use the service as long as your calls are to the US.
MyFreeLD.com requires a free software download and currently only works with Windows 95, 98 and NT.
Dialpad.com does not require a software download and install. They use a Java applet but they now state that it requires Windows 95, 98 or NT and IE 4 or Netscape 4.5 or later browsers.
You can find other free phone related services on the Free Fax & Phone Services page.