The ‘World of Warcraft Special Issue’ of Games and Gaming, Sage, October 1 2006, Vol 1 no. 4 is online here: http://gac.sagepub.com/content/vol1/issue4/. The issue features an impressive line-up of WoW/MMORPG essays.
Digital Games Research Association – DiGRA – Their website has a digital library of papers from the DiGRA International conferences of 2003 and 2005. Search under MMORPGs (for instance) to access lots of papers.
Play Between Worlds: Exploring Online Game Culture, T.L Taylor, MIT Press, 2006
See various papers on MMORPGs at Game Studies – The international journal of computer games research
Terra Nova, the big, interdisciplinary blog of virtual world research.
Synthetic Worlds: The Business and Cutlure of Online Games, Edward Castronova, 2005, University of Chicago Press (This reference applies to SL as well as WoW)
A recent paper, ‘The Use of Architectural Patterns in MMORPGs’, by Mattias Ljungström, found with the proceedings of the Aesthetics of Play Conference, online here.
Several of the Digital Games Research Association’s ‘Hard core columns’ have featured WoW. Tanya Krzywinska begins her article on methodology ‘ The Pleasures and the Dangers of the Game: Up Close and Personal’ with reflections on WoW. David Surman ponders tasks and trades in WoW, and the blurring of ‘work’ and ‘play’, in his article ‘Losing the Game: The Guilty Pleasure of Games as Work’. More recently, Christian Gerstner talks about moving the field of game studies to WoW in his article.
Constance Steinkuehler’s thesis focuses on Lineage but theories and methodology discussions are relevant to World of Warcraft.
International Journal of Role Playing is all in PDF-format, and is available from: http://journalofroleplaying.org/