The Early Bird registration discount for this year’s Worldwide Developers Conference (WWDC), which offers a savings of US$300, ends today. The five-day event, where Apple plans to unveil Mac OS X 10.3 “Panther,” runs from June 23-27 and features more than 170 scheduled in-depth technical sessions with new content designed to serve a wider range of Mac developers, including a dedicated track for QuickTime developers and content creators. WWDC will kick off with a keynote presented by Apple CEO Steve Jobs on Monday, June 23, beginning at 10:00 AM PT at San Francisco’s Moscone West.