Hartnell's "Who" was followed by Patrick Troughton in 1966, Jon Pertwee in 1970, Tom Baker in 1974, Peter Davison in 1982, Colin Baker in 1984, Sylvester McCoy in 1987, and Paul McGann in 1996.
Go to the Archive of archives for a list of all the Doctor Who-related archives on the World Wide Web.
For a listing of the episodes, and a short description of each one, check out Shannon Patrick Sullivan's Story Guide.
Each Doctor has various companions, picked up along his journeys. For more information on the companions, make sure to visit Jim Broderick's Guide to the Companions.
A lot of questions have arisen about the actual dimensions of the TARDIS. For the (un)official specifications, drop by Alstair Roberts's TARDIS Resources page.
A lot of fiction has been written by fans and posted to alt.drwho creative. Most of it has been archived by some of the readers of the group and can be found at:
For a look at some of the Doctors and of his (their?) companions, jump over to http://www.newwave.net/~greyhawk/doctor.html