Apple on Wednesday sent out invitations to the media for a briefing on its "iPhone Software Roadmap," which is expected to include information on the long-awaited iPhone software development kit.

The meeting, which is scheduled at Apple headquarters in Cupertino, Calif., may be an indication that Apple is highly unlikely to meet its self-imposed deadline of shipping the SDK to software developers by the end of February. Apple also said in the invitation that it would reveal "some exciting new enterprise features" for the iPhone.

Considering the iPhone is the second best smartphone sold in the United States behind the BlackBerry, many iPhone-toting businesspeople are eager for Apple to offer support for corporate e-mail systems, such as Microsoft Exchange. The SDK would also be a boom for software developers anxious to build applications that could run directly on the iPhone's operating system.

Currently, some third-party applications have been built for the iPhone but they are often based on breaking Apple's licensing agreement. The software ranges from applications that track down lost or stolen iPhones to a "Touchpad App" that turns an iPhone into a wireless remote track pad that gives a person direct access to their computer, as if using a mouse.

In introducing the iPhone in January 2007, Apple chief executive Steve Jobs had hoped developers would embrace his plan to have them use Web 2.0 technologies, such as Ajax, to build applications that would run in the iPhone's Safari browser. But developers unhappy with the limitations in such an approach started building their own tools for building apps to run on the iPhone, which shipped at the end of June 2007.

While no details of Apple's upcoming iPhone SDK have been released, such tools often include a compiler and hooks to an operating system's application programming interfaces for connecting to a variety of services. Having access to the innards of the OS provides the technology needed to build applications with far more capabilities than those running in a Web browser.