The Federal Communications Commission's plan to investigate the blocking of Google Voice over the iPhone signals the agency's new resolve to address public concerns about carrier control over an exploding mobile phone marketplace.

And the move couldn't have come soon enough. As millions of users are opting to upgrade to Internet-enabled "smart phones," carriers have begun blocking access to applications and the free-flowing Web by controlling what these phones can and can't do.

The agency's Wireless Telecommunications Bureau on Friday sent letters to Apple, AT&T and Google seeking answers to a series of questions about the blocking of the new Google application.

The FCC Steps Up

It's just the latest in an unfolding agency investigation into wireless practices.

Earlier Apple and AT&T decided to block Skype and Sling Media in the App Store, programs which compete directly with AT&T services. The carriers continue to maintain that the blocking of services and applications over the wireless Internet doesn't violate the established FCC standard for openness.

After less than a month in office, FCC Chairman Julius Genachowski is not buying it, and is taking a serious look at the lack of competition, consumer choice and openness in the wireless Internet sector.

The FCC announced in June that it would investigate exclusivity agreements that lock particular phones to carriers, while soaking consumers with high termination costs should they decide to go elsewhere.

But Friday's move takes the issue one step further, indicating the FCC's new "proactive approach to getting the facts and data necessary to make the best policy decisions," according to Chairman Genachowski.

The data on market concentration are pretty damning for carriers: Four wireless service providers (Verizon, AT&T, Sprint, and T-Mobile) account for 90 percent of the U.S. market. Across the board these carriers seek to have ultimate say over the phones and applications that can run on their networks.

They also limit Internet access to certain services, and keep subscribers locked down via predatory mobile phone contracts that levy massive fines against those who seek a better deal with a competitor.

AT&T Doublespeak

The FCC hopes to determine whether Apple and AT&T are working in collaboration to block certain wireless applications in favor of others. AT&T maintains that Apple makes all decisions on applications. But Apple seems to consistently block applications including Google Voice, Skype and Sling Media that threaten AT&T's bottom line.

This spring, Free Press urged the FCC to confirm that wireless networks must adhere to the Internet Policy Statement, which protects consumers' right to access any online content and services on any device of their choosing.

Surprisingly AT&T has in the past voiced public support for this position when its lead lobbyist Jim Cicconi was quoted in the Washington Post: "The same principals [sic] should apply across the board. As people migrate to the use of wireless devices to access the Internet, they...certainly expect that we treat these services the same way."

But while AT&T has acknowledged that open Internet principles should apply to the industry, it's acting to do the opposite: deciding what iPhone customers can and cannot do.

An Open Internet by Any Means

The FCC investigation is encouraging. At a time when carriers seek to become gatekeepers to the next generation of Internet access, the agency must re-assert our right to an open Internet -- whether accessed by desktop computer, laptop or mobile phone.

The right solution is to allow access to all applications and services without discrimination via any Internet connection.

If wireless carriers continue down the path of anti-competitive blocking and favoritism, Congress and the FCC should step in to set a better course.