Third-Party iPhone Application Development

Apple chose wisely to allow others to develop software for the iPhone. Not only can others profit from the popularity of the iPhone, fewer people will try to hack the iPhone to develop on it, thus making it more secure as the malicious hackers can no longer rely on the efforts of others to hack into the phone. But this decision will not make the iPhone completely secure: there will always be ways to break into it. Information on any electronic device will be completely secure only when the device is melted into an unusable mass.

Article on iPhone Development: http://www.informationweek.com/hardware/showArticle.jhtml?articleID=202403919&subSection=Macintosh+Platform