As of the 29th of July the people over at #iphone IRC channel have created the first known 3rd party application for the iPhone. It just so happens that it is an unauthorized program. It is a simple program which displays the message, “Hello World” and nothing else.
They have also released the source code for this program. The binary is available to download and has the community-built toolchain with UIKit. Not much is known of what the source code can do.
Now that one group has been able to do this much, others will definitely be able to get more interesting apps out there for everyone to use. It is unknown if Apple will block the ways the group was able to get the program built in the first place. Via Engadget.