The move puts Microsoft one step closer to an investment in Yahoo, though the software giant would most likely bid alongside other suitors.
Videos of the software, guarded by an NDA, have proliferated around the Web, showing off features Apple didn't during its keynote event.
Apple Officially Kills iPhone NDA, Launches Developer Forums
Source Code Runs Amuck After NDA Drop
It took Apple four paragraphs to rehabilitate its image among iPhone developers, paving the way for better iPhone software by letting developers share ideas.
Apple Drops NDA for Released iPhone Software
Nondisclosure agreement was a huge source of frustration among iPhone developers, who are now free to discuss their released software among themselves.
iPhone developers skirt Apple's NDA to promote apps
Adobe on why it is hosting the iPhone developers camp, NDA
Asus reveals next-gen graphics chip early