Apple has announced the dates for its annual Worldwide Developers Conference. The 2009 event will be held June 8-12, in its traditional venue of Moscone West in San Francisco, CA. As with last year’s event, Apple will be providing sessions focusing on both Mac OS X and iPhone OS X, as well as web app development. For the past two years, the company has also used the event’s keynote address as a venue for iPhone-related announcements, revealing the launch date for the original iPhone in 2007, and introducing the iPhone 3G at the 2008 event. It is unclear if Apple CEO Steve Jobs will deliver the keynote at this year’s event, as his six-month leave of absence is not expected to be over until the end of June.