Advanced Space Propulsion Study: Antiproton Annihilation Propulsion - A major new form of propulsion has just graduated from the never-never land of science fiction and has now become a serious topic for scientific and engineering investigation.

SpaceRef.com: Future Technology: Antimatter Propulsion - Small page, a few good links. Part of a larger interesting website.

NASA: Antimatter and Fusion for Rocket Propulsion - Page on fusion-antimatter hybrid space propulsion systems, mostly rockets.

NASA: Antimatter may propel future spacecraft to Mars - Marshall Space Flight Center: When Isaac Met Albert: using Newton's 3rd law, with Einstien's E=mc^2.

Popular Science: Star Travelers - Craft powered by antimatter, fusion, solar-driven sails may take us to interstellar space.