Macworld covers more details on the iPhone applications that were developed at the C4 conference.
The most impressive hacks/apps that were developed at C4 included the previously mentioned Lights Out game by Lucas Newman which demonstrates a full speed game written natively on the iPhone. It really is an impressive effort, and maybe the first application that makes it worth going through the various hoops to get an application installed on the iPhone.
A native version of Pong was developed by Jonathan Saggau and allowed control of the paddel using the iPhone's accelerometer, touchscreen or combination of both. The application even added two-player support over the network.
Finally, the Video Conferencing application by Ken and Glen Aspeslasgh won the competition to the oohs and ahhs of the audience.
Macworld notes that the video was not full speed and comprised of "pictures taken every so often by the iPhone's Camera and sent over the network."
Still, these efforts represent the most promising applications to date and can only get better. As more sophisticated applications are released, it becomes apparent how limiting the lack of an official development kit will be on the iPhone.