Relic News - The big name in the Homeworld game. An official relic site dedicated to bringing news related not only to Homeworld but all Relic games including the most excellent Dawn Of War series. Their forums are worth a visit.
Homeworld Shipyards - Complements to Arioch who maintains the site. It is truly an impressive site containing the largest collection of information on the Homeworld series, both factual and speculative. It also has nice ship by ship descriptions and preview information of Homeworld 2.
Real Time Strategy Carnage - A site devoted to Strategy games. The areas regarding the Homeworld franchise are particularly in-depth, containing large portions of information about each game and a list of mods which I find most useful at times :-)
Encyclopedia Hiigara - A Homeworld wiki, based on information from the game manuals and other sources.
Homeworld Access - Run by Homeboy, also the author of Homeworld Trinity, Homeworld Shots and the now defunct heclid link site. Features a gratitious amount of information and some downloads for you to enjoy.
Homeworld Trinity - A news site dedicated to all things Homeworld that are still alive and moving.
Homeworld Archives - Run by Troff, well known a few years back as the creator of the HW:Too comic. His site even hosted Jst-Online itself up until early 2007.
Homeworld Shots - Pictorial archive and screenshot hosting for Homeworld, Homeworld Cataclysm and Homeworld 2 by Relic Entertainment and derivative Game Modifications.
The HWU Screenshot Archive - A very old screenshot archive for Homeworld. Quite frankly, I am surprised it still exists, but then Strategyplanet is good at keeping sites up for a long period of time. This is the place to go if you like looking at unusual and almost freaky specially made Homeworld, Cataclysm and mod pictures, plus you can make them into lovely wallpaper! Medamanx the webmaster used to help Jst-Online out every now and then back in the day (Pre-2003!)