Apple's annual Worldwide Developers Conference happens June 8 through June 12 this year, at the Moscone Center in San Francisco. The event is by invitation only, with tickets opening up for registration today, allowing developers to sign up for the random selection process. Registration ends on April 17, at 10 AM PT, with the lucky devs who win tickets notified by April 20 of their selection. To sign up, you need to currently be enrolled in either the iOS Developer Program, the iOS Enterprise Developer Program or the Mac Developer Program (as of April 14 at 5:30 AM PT) and you'll be charged $1,599 US if you're selected to attend. This is the 26th annual WWDC, and it will offer over 100 technical sessions presented by Apple engineers with information about using new and existing developer tools to maximum effect. Hands-on labs are also available to those who attend in person, and for those who don't win a ticket in the random drawing, Apple is also live streaming select sessions throughout the event at the WWDC website and in the WWDC app. Recorded video of each technical session will be made available by the end of each day of the five-day conference. On tap for this year, it's likely we'll see Apple preview new versions of its major mobile and desktop operating systems, iOS and OS X, as that's usually what happens during the June event. Reports also suggest we could see Apple unveil a brand new streaming music service at the keynote, as well as new Apple TV hardware, along with an App Store and over-the-top video service. In terms of new Mac or iOS announcements, Apple could show off a new 15-inch Retina MacBook Pro, likely with the addition of a Force Touch trackpad and latest generation Broadwell processors, and we might also get our first look at the native SDK for building Apple Watch apps, which Apple has said will come sometime later this year.