Warner's Battletech Universe Warner brings us almost everything there is to Battletech. While there is little info on Mechwarrior 3rd Edition right now, he's in the process of a major page overhaul, so when all is said and done, it will probably be there. One of the biggest and most visited BTech sites on the Web.
Medron's Battletech PRI page. A page that strives to bring you the latest BattleTech software, be it shareware or payware. If you're looking for any BT related program, Medron will probably have it, along with many other interesting things. Medron is also a close friend to the Knight's very own Benjamin "Eagle's" Pryde.
Steel Command A web site that has the largest selection of Battletech information I have found. Current message boards, various online leagues, a plethora of information. If they don't have it, they know where to get it. Also in this family of pages are the oft-reffered to Dropship, Star League Memory Core, and Steel Command Leagues. Incidently, currently over 80% of the Dark Knights met and joined on these pages.