Media from around the world descend on Apple’s Worldwide Developers Conference in San Francisco every June for a chance to see a Steve Jobs keynote and to find out what shiny new objects he has up his sleeve.

This year, however, according to several reporters with excellent sources within the company, there may be no shiny new objects. And with Steve Jobs on sick leave, there’s a good chance the keynote will be delivered instead by marketing vice president Phil Schiller.

That would be a setback for the press. But the possibility of a Jobs no-show and the reports that the iPhone 5 might be pushed back to the fall didn’t seem to dampen the enthusiasm of the software developers for whom the week-long conference is intended (and who pay nearly $1,600 to attend).

Indeed, WWDC 2011 sold out in 10 hours, nearly 20 times faster than WWDC 2010 (which took 8 days to sell-out), nearly 70 times faster than WWDC 2009 (one month), and nearly 150 times WWDC 2008 (two months).

“Developers certainly seem to sense the way the wind is blowing,” writes Asymco’s Horace Dediu.

Dediu takes the growing interest in WWDC as confirmation of Jobs’ thesis that with the advent of the iPhone and iPad, the computer industry has moved beyond the traditional PC.

“The Post-PC era is evident in all kinds of data,” writes Dediu. “This set (developer attendance to mobile development) is particularly stark. It’s a proxy for investment and IT interest. There is a non-linear nature to this growth and history shows that non-linearity leads to unpredictable or unforeseeable change.”

Apple (AAPL), of course, is not the only player in the post PC game. For the record, Google’s (GOOG) Android developer conference, Google I/O, scheduled for May 10-11 in the same venue, sold out in 59 minutes.

Also on Fortune.com:

• Video: Steve Jobs’ WWDC 2010 keynote
• Video: Phil Schiller’s WWDC 2009 keynote
• Live blog: Steve Jobs at Apple’s WWDC 2008
  

[Follow Philip Elmer-DeWitt on Twitter @philiped]