Chances are that by now you are using Skype, Yahoo Instant Messenger with Voice, Google Talk, or one of the other PC VoIP phones that let you talk for free over the internet. You might also be a customer of Vonage, AT&T CallVantage, BroadVoice, or one of the other VoIP-based land-line replacements that give you flat-rate, unlimited calling and tons of great features like voicemail-to-email or click-to-call.
Link: O'Reilly Net
