Frederik L. Schodt's HomePage  http://www.jai2.com/Welcome.htm
Homepage of the author of several books on manga; includes descriptions and tables of contents from his books and a good set of manga links.

"Manga" entry, Wikipedia  http://en.wikipedia.org/wiki/Manga
Brief overview of manga, including origins, format, style, types of manga, manga distributors, manga magazines, etc. (Note for those unfamiliar with Wikipedia: this source is a free-content, collaborative website designed to be written, updated, and edited by its readers. The content of any Wikipedia entry can change at any time. All content should be verified.)

Matt-Thorn.com  http://matt-thorn.com/
Formerly the Shoujo manga page.  Created by a cultural anthropologist in the Department of Cartoon & Comic Art, Kyoto Seika University

Tezuka Osamu World  http://www.tezuka.co.jp/index.html
Official web page. Includes links to Tezuka Osamu museum, fan club, and information on the man himself.

Dragonball Archives (Japanese)  http://homepage3.nifty.com/hitoko/dbindex1.htm

Ohio State's manga blog  http://library.osu.edu/blogs/manga/
Provides an index to the manga titles held at Ohio State (over 1300) and a list of Japanese Manga Libraries and Museums