The Apple Worldwide Developers Conference, commonly abbreviated WWDC, is a conference held annually in California by Apple Inc.
The conference is primarily used by Apple to showcase its new software and technologies for developers, as well as offering hands-on labs and feedback sessions.
The number of attendees usually varies between 2,000 to 4,200 developers; however, during WWDC 2007, Steve Jobs noted that there were over 5,000 attendees.
WWDC 2008 was the latest conference, held at the Moscone Center in San Francisco, CA on June 9 of 2008.
For more info: http://en.wikipedia.org/wiki/Worldwide_Developers_Conference