A friend of mine in California introduced me to a new telephone service, Jajah. While using standard equipment - a regular phone or a mobile phone - it is actually possible to talk to each other for free (when both of the people talking are Jajah users).
"Calls between JAJAH users are FREE under the following conditions:
• You and your friends have to use mobile or landline phone in Zone 1 (USA, Canada, China, Singapore, Hong Kong, Taiwan) or a landline phone in Zone 2 (mainly Europe)
• Your friend's phone number must be registered in JAJAH as one of his source numbers
•Your friend's account must be "active" (an account will become inactive after two weeks of no operation like a free call, a cheap call or sending a SMS)
• You have not exceeded the FAIR USE policy: 1000 minutes a month, five hours a week, 1 hour a day" (http://www.jajah.com/content/freecalls.aspx)
They call it web-activated telephony and it works like this: I call my friend's number on the website. My own phone starts ringing. I pick up, hear a voice that tells me that I'm being connected, hear the telephone ringing - as if it was a landline/mobile phone call - and I wait for him to answer the phone. The sound quality is good. It does sound as if he's only a block away.