A free event, it is intended to spur on-site development of new iPhone-ready web applications and web sites.
Here's what the organizers say on the iPhoneDevCamp site:
Attendees will include web designers, developers, testers, and iPhone owners, all working together over the weekend to improve the web experience for iPhone. Development projects will include both solo and team efforts. While some attendees will wish to work solo during the event, we encourage attendees to team up, based on expertise, to work in ad-hoc project development teams. All attendees should be prepared to work on a development project during the event. You do not need to own an iPhone to attend (although, a large number of iPhones at the event will make the development and testing process much easier).
Attendees will be able to:
Create new web applications for iPhone.
Optimize existing web applications for iPhone.
Migrate Dashboard Widgets to web-based widgets for iPhone.
Test and optimize web sites for iPhone.
Friday (07/06): 6pm-10pm / Saturday (07/07): 9am-10pm / Sunday (07/08): 9am-6pm; Location Adobe, 601 Townsend Street, San Francisco, CA 94103