WengoPhone

For Free software enthusiasts WengoPhone is the perfect tool to make VoIP calls to conventional phones and calls between PCs

Not only that, also you can send SMS messages, conduct video conferencing or chat with contacts from MSN Messenger, Yahoo, Jabber or AIM.

WengoPhone is an open source application that is an alternative to ones such as Skype, which is proprietary software. Although its operation is similar to Skype,in order to perform certain activities, such as calling or sending SMS telephones, you must purchase credit program.

Of course, international calls to both fixed and to mobile phones are cheaper. Consultation rates in the web application.