Though it's just a rudimentary "Hello World" application, members of the iPhone Dev Wiki team are reporting that they have successfully compiled and launched the first third party application on the iPhone. According to the Dev Wiki website,
"The iphone-binutils project has now correctly assembled and linked Hello World, using entirely free software. The resulting binary runs correctly on the iPhone."
This most recently achievement was made by Patrick Walton (aka Nightwatch), who was also responsible for one of the earlier milestones in attempts to hack the iPhone, termed "getting out of jail".
For those who are interested in giving "Hello World" a shot, there are instructions available. We recommend only experienced users give this a shot. Otherwise, you risk bricking your iPhone simply for the thrill of a Hello World application.This most recent accomplishment puts this particular team approximately 2/3 of the way to a fully unlocked iPhone, according to their list of required goals.