moon_aka_sun

Conlang Page: FAQ, Library (~1430 languages)
Conlang list (~1850) at Langmaker | Blue index | Babel Text
Conlang list (312) w/short descriptions
Conlang Directory (rather old)
Yet another list and more links (650+ langs)
Essays on Language Design, esp. Lexical Semantics
Artificial Language Lab, News | Optimal IAL, Plan B | Verb aspects, casuatives
Language Construction Kit | Zompist links | Forum
Bibliography of Planned Languages
Conlang Mailing List, Archive | NewsGroup
Case schemes | Meaning change (mainly Engl.)
Искусственные языки | Статьи | Форум | Ру-Сиб
Other conlang links
Usenet newsgroup: news:alt.language.artificial

Loglan.org | textbook (1999) | Loglan/ru | w:loglan
Lojban | too | lojban for beginners | w:lojban
Katanda → LS (2003)
Nasendi (2003), Latenkwa (2004), Ladekwa (2005), Latejami (2006) [Y!] → LS
Ceqli | w:ceqli
Ro | Ro | w:ro
Toki Pona | w:tokipona
Voksigid
Minyeva
YALL || ygyde || tunu || yiklamu
Danovën | w:arovën
E-min (not a loglan exactly)
Abakwi || akbiekdi
Ido (improved/fixed Esperanto) | Ido dicts | ido.wikipedia | w:ido
Vorlin | V-1999 | w:vorlin
Sona | w:sona
Interglossa
Novial | Lingwa de Planeta
And finally Learn NOT to speak Esperanto
Yet finallier Farewell to auxiliary languages

And this is just for fun: Jabberwocky | The Zompist Phrasebook

IPA Tables Chart Sounds | Writing systems @ Omniglot

Upd. Ilaksh Ithkuil