Bob Atkins has created a website with a complete database of lens information.

LensPlay is a website devoted to photography, more specifically to photographic lenses. Currently it contains extensive information on lenses compatible with the Canon EOS series of cameras. As the site is developed, more lenses may be added and a gallery section is planned. [ more ]

There are currently 180 different lenses in the database and 595 individual reviews of the various lenses. I feel this will become an excellent resource as he builds out the database. I'm also very happy that he started the database with the Canon EOS lens mounts as well.