Free Internet Phone Calls
Update: Things have changed a bit since this article was written in the 1990's. The dot com bubble burst and for a number of years there was no free PC to phone calling. However, now, not only can you call regular phones for free, you can also get a free number for incoming calls. Read this article about combining Skype and StanaPhone for one excellent and totally free phone service. The original article from the 90's follows:
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.