Online Game Developers Conference 2007
Aimed predominately at the techncial side of online games and related entertainment, this will be held in May 2007 in Seattle.
My advisor is submitting a proposal to talk about cross-functional teams, which is on the usage side of the topic, so I am hoping that similar talks will address the uses - particularily educational - of online games and worlds.
For more information, check the ODGC website periodically. At the moment, they do not have anyone other than the keynote speaker listed (a woman, btw, which is unusual given the stereotype of male developers....), but I assume the agenda and speakers will be listed by March.