Bibliography of Planned Languages (Excluding Esperanto): List of books on interlinguistics, Volapük, Ido, Ro, Occidental, Novial, Interlingua, Glosa, modified English and Latin, pasigraphies, number languages, and other planned languages.
Conlang Free City: This Conlang Wiki is devoted to the topics of ConLangs and ConCultures. This is an online resource and communnity about Conlangs that you can edit.
Conlangs DE-Cal: A class on constructing languages at the University of California Berkeley.
Constructed Languages: Links to many conlang sites as well as the author's own conlang.
Constructed Languages: An encyclopedia entry describing constructed languages, including sections on auxiliary languages, artistic languages, and logical languages.
Earth Minimal Language: Complete 220 word second compact language.
Phonetic Picture-Writing: Phonetic picture-writing can also be read phonetically. Its ideograms are composed of special letters. Authored by Leonhard Heinzmann.
Universal Language Dictionary Project: An attempt to create a list of concepts, described in English, along with words to express those concepts in several natural and artificial languages.