Via elamb, The Register has an article on hacking World of Warcraft, and also mentions an upcoming book I didn’t know about, Exploiting Online Games: Cheating Massively Distributed Systems, by Gary McGraw and Greg Hoglund.
Exploiting games like this, as I’m sure the authors posit, is something that might not interest a lot of people, but should still be watched. Things like WoW (12 million users! This has become a social network in itself, really!) and Second Life bleed over into the real world, both in relationships with fellow people and business realms. But beyond that, the distributed worlds of gaming on such a large level will, just like the hardware gaming pushes, eventually find more mainstream uses. Being able to know these risks (like offloading some of the work to the client machines), at least just being aware of them, should prove useful someday.
I’ll get this book regardless, since I play WoW  and I’ve seen things in past games that exemplify the issues with cheating . It helps a lot to know what is possible out there, and can put the whole gaming world/experience into more of a perspective. The book also looks like it will explore the issues that the game software presents to the users, for instance how far the game software can go in monitoring the user. Thankfully I run gaming on a separate box which does nothing but burn discs and run games, but I’m a rarity in that setup.
 I have a 60 Warlock (main) and 60 Priest on Crushridge Alliance, and a 55 Shaman on Kul’Tiras Alliance. Obviously I’ve focused on the Shammy since BC.
 Aimbots in Quake 1 (yes, some people earned money using them); farm bots in Diablo II/Battlenet.