Apple has released its official application for WWDC attendees. It's available over at developer.apple.com/wwdc/app and requires you to login with the same account you used to purchase your WWDC ticket.
The app looks great, one of the nicest things Apple has done on the iPhone in a while. You can use it to check sessions and mark some as favorites, receive updates and quickly swipe through days. As you can see, it also comes with two useful "now" and "filter" buttons on top. Last, you can browse the suggested WWDC locations. Moscone Center, Yerba Buena Gardens and some parking spots are in there.
Great idea, recommended for all those who're going to the WWDC 2010. Check out the iPhone screenshots below.