Wormholes

What Exactly Is a "Wormhole"?
Have wormholes been proven to exist or are they still theoretical? From Scientific American's "Ask the experts", with answers by Richard F. Holman, William A. Hiscock, and Matt Visser.
http://www.sciam.com/article.cfm?id=follow-up-what-exactly-is

White Holes and Wormholes
Illustrations of White Hole and wormhole geometry, plus a visualization of what the view through a wormhole would look like. One of Andrew Hamilton's excellent pages about visualizing relativity.
http://casa.colorado.edu/~ajsh/schww.html

Why Wormholes?
Brief article by Matt Visser (Victoria University of Wellington) about why the concept of a wormhole, originally more science fiction than science, has become interesting for serious physicists.
http://www.mcs.vuw.ac.nz/~visser/general.shtml#why-wormholes