A federal probe of practices in the wireless industry could have significant implications for school leaders and others who use smart phones and other wireless devices to communicate.

In particular, the Federal Communications Commission (FCC) is examining the competitive practices of Apple Inc. and other companies that make smart phones–and their process for approving or denying applications developed to run on the phones.

The FCC’s actions could affect the choices educators and other consumers have with regard to smart-phone applications, such as Google Voice–a program that gives users an additional phone number that’s not tied to any one phone line, a useful application for busy school administrators on the go.

In the latest chapter in the FCC’s probe, Apple told federal regulators last week that it blocked Google Voice from running on the iPhone because it alters important functions on the device–yet the company denied that it has rejected Google’s application outright.

“Contrary to published reports, Apple has not rejected the Google Voice application, and continues to study it,” Apple said in an Aug. 21 letter to the FCC.

The agency is looking into Apple’s blocking of Google Voice as part of its examination of the consumer implications of wireless industry practices. It sent queries to Apple, Google, and Dallas-based AT&T Inc., the only wireless carrier to offer the iPhone in the United States.

AT&T and Google also responded with letters to regulators on Aug. 21. AT&T said Apple did not consult with the company before turning Google’s program down. Google kept confidential the parts of its letter describing Apple’s reasons for rejecting Google Voice.

Users can program Google Voice to direct incoming calls first to a cell phone, then a work number, and finally a home number, for example. They can set up voice mail and have Google Voice eMail transcripts of their messages. School leaders also can use Google Voice to send text messages and place calls–even international ones–at low rates paid to Google, not the carriers. Those calls do burn regular cell phone plan minutes, but the idea has prompted widespread speculation that Apple and AT&T saw a Google Voice app for the iPhone as a potential competitor to their monthly mobile plans.

Apple said it rejected the program because it replaces the iPhone’s own interface for making calls and sending text messages with a Google version. The company said it blocked three other developers’ programs for the same reasons.

Apple also said it was concerned that Google Voice would send the contents of people’s iPhone contact lists to Google’s servers.

“We have yet to obtain any assurances from Google that [these] data will only be used in appropriate ways,” Apple said. “These factors present several new issues and questions to us that we are still pondering at this time.”

The Google Voice snafu comes as competition between onetime allies Apple and Google is heating up. Google has its own cell phone operating software, called Android, and it recently announced plans for a computer operating system that could challenge Apple and its Macs.