http://www.comicstripgenerator.com has hundreds
of customizable cartoon cel images where you can
change the quote/caption/joke/phrase in the text
bubbles and thought bubbles.

Here are some Anime/Manga links as samples:

http://www.comicstripgenerator.com/create-right.asp?cartoon=anime

http://www.comicstripgenerator.com/create-right.asp?cartoon=gundamn-anime

http://www.comicstripgenerator.com/create-right.asp?cartoon=anime-cartoon-cel

http://www.comicstripgenerator.com/create-right.asp?cartoon=dragonball-z-anime

http://www.comicstripgenerator.com/create-right.asp?cartoon=sword-fighter-anime-cel

http://www.comicstripgenerator.com/create-right.asp?cartoon=anime-character-generator

Find more fun web based generators on:
http://www.sparesomechange.com/funny/generator.htm

Please reply with links to some great pages where I
can obtain more images of cartoons (anime, manga,
tv shows, comic clip arts, etc). Also looking for
tips on how to make site more user friendly ;)