The Dickens Page
http://lang.nagoya-u.ac.jp/~matsuoka/CD-TTC.html
A scholarly site with links to essays and the full text.
The Victorian Web
http://www.victorianweb.org/authors/dickens/2citiesov.html
Illustrations and study materials relating to the novel.
Dickens
http://lang.nagoya-u.ac.jp/%7Ematsuoka/Dickens.html
General articles including biographical information.