Callserve Internet Telephone
Full user review
"Cheap, easy to use internet telephone for outgoing calls only"
The software is easy to install and use. You will need high speed internet (I use 1.5 Mbs DSL) and a microphone and speakers. My wife and I make calls to Chile regularly from the United States. We normally get very clear, quality connections. It's hard to beat the price. I have also used Callserve to make calls from Japan to the United States.
Some times calls will not connect but it is unclear whether it is due to heavy internet traffic or heavy volume on the Chilean phone system. At any rate, poor connections are fairly rare. The system cannot be used to accept incoming calls.