Online Tsunami — Rachel Benn's Javascript-​based helper/solver and puzzle collection
http://​www.playtsunami.com/

Griddlers Net — “Extended Paint by Numbers online puzzles, new puzzles published everyday. Free fun.” — Includes colours and isometric puzzles; a community of solvers!
http://​www.griddlers.net/

Web Paint-​by-​Numbers — A community site with a JavaScript helper
http://​webpbn.com/

▒LOGICHOME▒ — A site for Korean fans to share puzzles, by 김경래 (Kyungrae Kim); includes a Java helper
http://​www.logichome.org/

Nonogram :: Paint by numbers :: Japanese crosswords :: Pick a box :: Logic Square — Includes a Flash game and a discussion forum for Nonogram enthusiasts
http://​www.nonogram.net/

Nonoriddle - An enigma wrapped in a puzzle — A Javascript game where the dotted squares reveal a riddle
http://​www.nonoriddle.com/