Users download the free application off the Web, but instead of typing a text message, they use a headset, telephone or microphone and speakers to make a high-quality, two-way voice call to anyone else running the application.

FORBES: Skype Proves Anyone Can Sell Phone Service

The two companies are already developing a range of cheap and portable Internet appliances that will enable people to use on-line services as routinely as they make a telephone call.

ECONOMIST: Internet riders