I know this site is dedicated to the Forgotten Realms but I have also a question about the Dark Sun campaign setting. I just found a second edition campaign boxed set in my local shop and bought it. I was wondering if there is also a third edition source of it in dragons or dungeon magazines?
There is no "official" 3e full conversion of the Dark Sun setting. Paizo published both a special issue of DRAGON [#319] and DUNGEON [#110] which update "parts" of the setting, the races, etc -- they function like a 3e PHB and DMG for DS.
Otherwise, the only 3e work being doing for Athas resides at the site Blake indicated above.
May I ask if and what your planning to use Darksun for anytime soon? Because a full understanding of the psionics rules is adamant for playing on the burning world of Athas.
I knew someone who used the conversion rules from the dragon mags and who liked using psionics. It was a real blast playing in the city state of Tyr with 3rd edition and experimental gestalt rules. Encountering psionic streetgangs who bully with their mind was a real eye opener to the power of a psionics filled world. Be wary and give players higher than 2nd level PC's to start with. Otherwise they will end up in the dead book in no time.
You do know Athas is very difficult to reach via planar travel or spelljamming because the Crystal Sphere of Athas is situated in a planar storm of a sort. So it's not easy to explain putting stuff from other worlds on the burning planet, or dropping a realms party into Athas.
Ooh I do love the story of the cataclysm caused by magic gone horribly wrong, defilers and preserver mages, Muls and Thrikreen, the bone (splinter on a natural 1) weapons. Man i wanna join in! Alas