When Apple releases its SDK, more applications like this could become available, just as they are on PCs and Macs today. However, details on the upcoming SDK are scant, and McGuire guesses that Apple won't open much of the functionality of the phone. "I suspect that it's not going to be a wide open SDK," he says. Programmers might have access to certain layers of the phone's underlying software, such as the instructions that allow widgets to access the Internet, but Apple may keep the instructions for accessing the accelerometer, for example, under wraps. "Apple likes to keep things locked down," McGuire says.

He adds that the control is essential to ensuring that the iPhone works well for most of the people most of the time. In addition, Apple's control is important for ensuring software stability and security--two important criteria if the phone is to be used in the business setting. "I get the impression that [Apple] wants to make [the iPhone] somewhat corporate friendly," McGuire says. "I think you're going to see a lot of focus on pulling developers in to make form-based applications"--the kind used in a sales environment, for example. He says that he suspects Apple will treat third-party software the same way that it approves iPod accessories: by requiring vendors to register with Apple to acquire a badge noting Apple's approval. In this way, Apple could maintain some control over the quality of outside applications, which could help make them more secure.

Regardless of the access the SDK provides to programmers, and the safety precautions available for certified third-party programs, the hacking community will continue to innovate around the iPhone. "Even without the official SDK," says Kasatani, "it's much more attractive than Windows Mobile." The Mac operating system and user interface are more fun to use, he says, and the multitouch display makes it especially interesting to work with.