While the fever for the iPhone builds, some anxiety is also building within Apple as the iPhone ship date of June 29th approaches, according to the New York Times.

Despite what some are calling "the God machine," and incredible expectations for the Apple iPhone, some Apple executives are on the edge of their seat. Some worry that that "expectations for the one-button phones may be too high and that first-generation buyers will end up disappointed," John Markoff wrote.

Skeptics have worried that the price is too high. The network that the iPhone uses is slower than some other rival’s, and some of those rivals are also counting on the iPhone’s lack of a physical keyboard to limit its attraction for business users.

One competitor who declined to be identified declared, "It�s very media-centric."

Even so, despite the anxiety inside Apple and the angst by competitors, Apple may have come across at just the right time. "These devices have become ubiquitous, and there�s an enormous hunger out there," said Peter Schwartz, the chairman of Global Business Network, a consulting firm in New York. Some other analysts believe that the iPhone is shifting the balance of power in the mobile phone market.

Nevertheless, to defuse any concerns about the intial design of the iPhone, Apple has announced that they will be publishing updates to the iPhone software . That will go a long way towards reacting to the marketplace and deflecting critics.

There are also lingering concerns about whether and under what conditions Apple developers will be able to write software for the iPhone. Initially, Apple said no. At the recent WSJ: All Things Digital Conference, Mr. Jobs opened the door a little. But he’s still concerned about security and the quality of the software. Developers may get the definitive ruling from Mr. Jobs at the WWDC Keynote.

Apple executives will certainly breathe a sigh of relief when the iPhone takes off and all the skeptic’s and competitor’s FUD is just a memory.