Advanced Space Propulsion Study: Antiproton Annihilation Propulsion: A look at the properties of antimatter and its manufacture, storage and use.
Antihydrogen - A New Energy Source?: Explains why the answer to this question is "No."
NASA: Antimatter and Fusion for Rocket Propulsion: Fusion-antimatter hybrid space propulsion systems for fast transport to Mars and beyond.
Positronics Research, LLC: A research firm located in New Mexico, pursuing antimatter storage and utilzation for high energy applications in propulsion and medical arenas.
When Isaac Met Albert: Antimatter propulsion: using Newton's 3rd law combined with Einstein's E=mc^2.