Lord Jerrec's Lair

Features guides on lockpicking, traps, and training. Also contains general information on Voln, herbs, critters, and verbs.
http://www.jerrec.com

The Underground

An organization dedicated to roleplaying pickpockets in Elanthia. Contains roleplaying tips and examples.
http://thievesden.www3.50megs.com/

Lord Terratons Stonghold

Information on box traps, herbs, spells and history. Features a message board and programs.
http://www.geocities.com/TimesSquare/Castle/4507/Frames.html

Midgar's Rogue Guild Erudition

Features detailed information for Rogues players including a guild skill list and bestiary.
http://www.angelfire.com/rpg/midgarzolom/MidgarErudition.html