By all accounts, the term first appeared in the media on, where else, Fox News: a December 21, 2009 segment, guest-hosted by conservative talk show host Laura Ingraham, was called "Controversy Surrounds Ground Zero Mosque/Cultural Center."
From there, though, the term experienced nothing like the meteoric rise of the term "Death Panel." Months later, the Associated Press began tagging their items with the term, but it didn't appear in the media coverage of the issue again until May. Specifically, it came up on May 16, in a New York Post piece titled "Short on Allah Dollars; Ground Zero Mosque Team Lacking Funds Amid Bookkeeping Chaos.
Four days later, the Post was at it again. In an article titled "Long Arm of Allah," the Post chronicled a separate controversy over a proposed Brooklyn Mosque. "Unlike better-organized residents of lower Manhattan, who cry, "Hell no!" to the Ground Zero mosque, those who defy the one in Sheepshead Bay have been crucified in local papers for making entirely defensible statements," wrote Andrea Peyser.
That same evening, Fox host Sean Hannity ran a complete segment about Imam Feisal Abdul Rauf, the man behind the "Ground Zero Mosque."
On May 21, the New York Daily News argued that Rauf himself foisted the term to prominence by seeking a public vote on his initiative. "Although the project needed no public approvals because it fit the local zoning, Rauf's organization voluntarily presented the concept to a committee of Community Board 1, which unanimously passed a supporting resolution," reads a Daily News editorial. "That vote led to the facility being dubbed the 'Ground Zero mosque.'"
It was then only days when the term entered the bloodstream of the mainstream media. On May 23, ABC ran a segment titled "FLASH POINT; Ground Zero Mosque."
And two days later, the Associated Press itself made it official: "Groups to present NY ground zero mosque plans."
As Justin Elliott at Salon has demonstrated, the "controversy" about the mosque got much of its juice from conservative blogger Pam Geller. A quick Nexis search confirms this.
Politico's Ben Smith countered that Geller's role was to stoke grassroots opposition, not pique media curiosity. That honor, Smith argues, goes to conservative Allen Roth. But the term itself seems to have obtained media prominence largely without help from the political team that brought you "death panels".