Streaming refers to sending audio and/or video from your computer to a server that is running a streaming program like Shoutcast, Icecast, Windows Media Server, Quicktime, or Helix..  Those programs then make that audio or video available for remote listeners.  Worldbridges currently uses Shoutcast to stream its webcasts.  Depending on audio bitrate and other variables, there is usually a delay ranging from 20-100 seconds between the time the audio is produced and the time it is heard by remote listeners.  
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Producing a stream of audio with only one source of aud­io (music or one person speaking) is relatively simple.  Producing a a stream of audio in which multiple sources are streamed (i.e. a multi-pers­on conversation) is more complicated and requires the tools and methods covered in the 'Recording both ends of a telephony call' section of this book.   While it is possible to record both sides of a telephony call using 3rd party programs like Powergramo and Pamela (more info here) we have thusfar been unable to use those tools to actually stream. The tools used to stream vary significantly by operating system.