Oops - it seems that the iPhone's application key data has been leaked by a programmer - who is almost certainly going to get his wrists smacked by Apple.
According to the Austin Heap Web portal, the software development key data is now in the public domain.
As we all (should) know, all iPhone applications must be properly signed for iTunes to process them and for the iPhone to load them.
With the application key, almost anyone can now (alegedly) code up a kosher application to create home-brew iTunes applications.
Put simply, this means that some could code up an MP3-compliant application that uses the iTunes format, allowing an iPhone user to play unapproved MP3 tracks. And games. An utilities.
I think Apple will be a tad worried about this...