Initiating a probe into the Apple rejection of Google Voice for the iPhone, and the pulling of 'previously approved' Google Voice-related software from the company's App Store, the Federal Communications Commission (FCC) has sent a letter to Apple.

In his letter, James Schlicting, FCC's acting chief of wireless telecom bureau, said: "Recent press reports indicate that Apple has declined to approve the Google Voice application for the iPhone and has removed related - and previously approved - third-party applications from the iPhone App Store. In light of pending FCC proceedings regarding wireless open access and handset exclusivity, we are interested in a more complete understanding of this situation."

In addition, the FCC has also written to Apple's exclusive carrier partner in the US - AT&T; as well as Google, asking them to give their respective versions of the Google Voice rejection episode.

Asking Apple to specify whether the decision of rejecting Google Voice, and casting off other similar applications, was taken by the company alone or "in consultation with AT&T," the letter seeks from Apple a complete description of the conversations between the partners in case the decision was jointly taken.

Among the other questions the FCC has asked Apple include - AT&T's role in approving iPhone applications; how Google Voice differs from any other approved VoIP software; and the App Store approval process.