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.

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.

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.