Confused? A Guide

Here's Your Guide to Citizen Journalism, by Mark Glaser at NPR's Media Shift.
Well, is citizen journalism even new? Glaser sites two examples:

...in the modern era, video footage of the assassination of President John F. Kennedy in the ’60s and footage of police beating Rodney King in Los Angeles in the ’80s were both captured by citizens on the scene.

Lots of this is attributed to Dan Gillmor, and is a good overview of the topic with lots of links for more background.