These are some of the Dark Sun links I usually browse. For a complete listing of DS web pages, visit the Silt Skimmer page, below.
The Burnt World of Athas - official source of information for DS3e
Athasian Atlas - an excelent way to keep track of the party's journey.
Archives of DARK-SUN-L@ORACLE.WIZARDS.COM - files from the mailing list
DarkHelm.net - a different take on advanced beings
The Dark Sun Gallery - new pictures depicting Dark Sun creatures
Dark Sun Message Boards - another way to change messages and ideas about the DS setting
The Silt Skimmer Page - a great page with the largest (and most complete) list of all Dark Sun sites on the Internet.
D&D at Wizards - rules and new stuff for D&D
Open Gaming Foundation - D20 rules, for free
Wizards D20 - 3.5 rules for free
CyberDark - a page about a Cyberpunk/Horror RPG I wrote (in Portuguese)