Alien Observer
Report UFO Sightings, explore their huge information warehouse covering the UFO enigma. Lots of links, alien and UFO paraphernalia, discussion board.
National Investigations Committee on Aerial Phenom
A portal of UFO evidence, research tools and links to related sites.
Project-UFO Database & Search
UFO information with web search and Database of ufo sighting around the world.
Sitchin Links
Library of links of Sitchin's writings and books, Mars connection, and web sites tracking UFO's.
UFO Links
UFO research, sightings, reports, theories, merchandise, organizations. Hangar 18, Area 51, crop circles, extraterrestrials, Roswell crash.
UFO Skeptic's Toolkit
Contains lots of UFO material and some newsletters.
UFO's and the Paranormal
UFO sightings and paranormal reports. Extensive portal to UFO and paranormal research and resources.
UFOs
A compendium of independently reviewed and categorized links dealing with the UFO question, also contains editorial comment and helpful micro-essays.
UFOs and Extraterrestrials
Devoted to UFO and UFO related web sites. Many areas of Ufology are covered, including; aliens, saucers, cattle mutilations, government involvement, Area 51. Has links to UFO reports, investigations of sightings, pictures, videos. Also contains a newsgroup list, some web rings, and other UFO related information.
UFOS/Aliens from about.com Guide
Weekly features, UFO Timeline, links, latest UFO sightings, UFO sightings database, bulletin board, and chat.