English

Fantastic Fiction
http://www.fantasticfiction.co.uk
Frequently updated British site featuring exhaustive bibliogaphies for thousands of fantasy, horror, and science fiction writers. Plot summaries, publication information, and book cover scans are available for almost every title included.
Subjects:   Popular Fiction  

ComicsResearch.org
http://www.comicsresearch.org
Provides bibliographic information for books about comics in general, from specific countries, cartoonists, comics by genre or subject area, title & character and more.
Subjects:   Popular Fiction  

Romance Reader
http://www.theromancereader.com
Comprehensive site featuring news and reviews for the Romance literature readership. Readers provide a great deal of content, lending a vigorous community-like environment to the site.
Subjects:   Popular Fiction  

Stop, You're Killing Me!
http://www.stopyourekillingme.com
A killer site for tracking characters in your favorite series. Books are arranged by author, series character, and by date written. Useful lists in the author section feature characters' jobs, locales, time periods, etc., and also include the ever-helpful "If you like...you might like..." classifications.
Subjects:   Popular Fiction