I cannot remember the last time that the mainstream press took notice of any equipment vendor announcing a software development kit, but clearly Apple is not just any equipment vendor and the iPhone SDK is not just any SDK. The SDK that Apple just announced provides more functionality and fewer rules than some observers expected, but has still generated some justifiable and not-so-justifiable complaints.

The first news story I saw about the SDK announcement focused on Apple's planned inclusion of Microsoft Exchange ActiveSync and other business-friendly features in the next release of the iPhone's software. It only mentioned the SDK in passing as a way that third-party software developers would be able to create software for business customers. The general thrust of this as well as a number of other stories was: Watch out BlackBerry, Apple is coming.

Later the same day the predominant theme was that developers were enthusiastic about the potential offered by the SDK but were annoyed by some restrictions, such as only distributing the software through iTunes and not allowing VoIP over the cellular network. By the next day many stories started to focus on the contractual limitations, including no background processes, no use of unpublished API features and no use of plug-ins.

None of the stories I saw talked about what I think is the most important aspect of the SDK - Apple is admitting that the iPhone is a computer running a good operating system - the very thing I pined for a few months back.

Some restrictions that have been talked about make sense. It is hard to see that Apple or its partner telcos have much desire to enable telco bypass over the telco networks. So it's hard to see that anyone who thought about it should have been surprised that VoIP over the cellular network is contractually prohibited. But it is a bit surprising that VoIP over the Wi-Fi net was noted at the announcement as specifically not being prohibited.

This means that an iPod Touch, running VoIP, will quickly become a phone of choice for people who tend to work, live or stay in Wi-Fi-rich environments (like the Holiday Inn Express I'm writing this column in). Another restriction that may turn out not to be as strict as it looked at first glance clearly makes sense as a best practice - you do not want lots of applications running in the background running down the battery. And, I fully expect that Apple will announce a way for enterprises to run their own iTunes-like servers for software distribution.

There will always be some restrictions because Apple does want to protect the iPhone from applications that would make it unreliable or not secure, but I expect that the restrictions will do little to inhibit what looks like will be an explosion of new applications over the next few months. The explosion will only partially be fueled by the new venture-backed US$100 million iFund that will help developers come up with iPhone applications. The presence of real development money means that far more polished products are likely to result.

One news story reported that "Steve Jobs unveils plans to dominate RIM BlackBerry, Life, the Universe, and Everything." That headline may have been tongue in cheek, but if the developer crowd heads the way it just might now that it's been enabled, the headline might not be all that far off.