Ad Astra Per Magica
History and player aids from a long-running Spelljammer campaign.
Ahzad Jinsai's Spelljammer Page
Features house rules, a chat room, maps of the Flow, and an index of noteworthy characters.
Celestials
Character profiles and summaries from a play-by-e-mail campaign.
Daggerdale's Spelljammer Lore
Information on converting a Forgotten Realms campaign into a Spelljammer game set in Realmspace.
Despoilers of the Phlo
Background, rules, and summaries of a chatroom-based campaign.
Dragon Dreams
Alternate rules for wildspace travel.
Hyrkulspace
Features a new crystal sphere and a Spelljammer chat room.
Magical Book of Jordan Silverton
Features a list of known crystal spheres and several ships with crews.
Shadow of the Spider Moon
Supporting material for the "Shadow of the Spider Moon" d20 mini-game from Polyhedron #151.
Spelljammer Anonymous
New monsters, ships, and crystal spheres.
Spelljammer Crew Info
Online form that generates detailed NPC ship crews.
Spelljammer Pages
New ships and crystal spheres.
Spelljammer: Beyond the Moons
Official website features 3e conversions and a collection of monsters, ships, magic, characters, and rules from various contributors. Also hosts Into the Void Magazine and the SJML Archives. Accepts submissions from the public.
Spike's Hammer
Races, NPCs, monsters, crystal spheres travel, spells, magic items, planar travel.
The Shattered Fractine
Dedicated to converting 2nd Edition spelljamming to 3E/d20 rules.
The Star Change
Campaign background, character profiles, and summaries from a play-by-e-mail campaign.
WebRing: Spelljammer on the Web
Collections of sites dedicated to this world.
Wolf's Spelljamming Port
Features new ships and a new crystal sphere, Saruspace.
World of Arkaela
Dedicated to the fusion of the characters from Julian May's 'Many Coloured Land' Books with the Spelljammer campaign setting.