Apple.com has just put up this year's World Wide Developer Conference (WWDC 2010) page, and as suspected the dates are early -- June 7-11 at the traditional Moscone West venue in San Francisco.
For the last two years, Apple has also used the even to debut new iPhone hardware and release dates, with the iPhone 3GS in 2009 and iPhone 3G in 2008. The iPhone 2G was announced at Macworld in 2008, but its release date was made public at WWDC as well. All that to say it's fairly likely WWDC 2010 will not only give us our first official look at the 4th generation iPhone (iPhone HD, iPhone 4G, iPhone G4, whatever floats your moniker boat), but word on when we'll get it as well.
While the iPhone has only been part of WWDC for 3 years, given the app-centric nature of the artwork (above) its fair to say it'll be given the lion's share of attention this year.
UPDATE: It's iPhone OS-centric to say the least. Apple Design Awards, the Mac need not apply, and the course tracks listed are predominantly iPhone OS (iPhone, iPad). That's clearly where Apple is shifting their attention, at least for this year, and given their increasing iPhone OS earnings, it should come as no surprise.
The shot's been sounded people, the race to the next iPhone is on!