I'm always looking for more links, so please let me know.

English
Aestheticism's Patarillo Page
Fic:
Lianne's Homepage One Patalliro/Sentinel crossover.
BT's The Unbearable Sweetness of Being Deadly (Eroica/Patalliro crossover) and Day and Night.
MJJ's Baghdad on the Seine and its sequel Lowlands (Eroica/Patarillo/Papuwa crossovers).
My stuff For the 30 kisses challenge.
Cock Robin Ondo Livejournal Community
Blog post about Patalliro

Japanese
Hakusensha's Patalliro Official Homepage
Toei Patalliro Page Anime information.
Toei Anime Broad Band A site offering different episodes every week, if you pay 1050 yen a month. You can watch the opening theme song and previews for some of the episodes for free.
Patalliro Saiyuki Kids Station mini-site for the new anime.
Ukigumo: Patalliro A summary of the first 30 vols and links.
Pata-chara Record Character and chapter listing, and information.
Mineo Maya wa Midashi Fan Page
Patalliro Investigation Report T An explanation of references and jokes.
Patalliro Investigation Report (Rakugo) An explanation of rakugo references and jokes.
Patalliro! Makai Shinshiroku (Who's Who of the Demon World) Information on characters from the Demon World story arcs.
Shine on, Tamanegi Corps! A listing of all the Tamanegi and Patalliro's relatives, plus anime information.