Marchex announced today that it would pay up to $62.5 million in cash and stock for Jingle Networks, the 1-800 FREE411 ad supported service. With the addition of Jingle Networks, the Marchex Call Advertising Network will now have an annualized reach of more than 500 million phone calls across digital media, including mobile. In addition to ad inventory, Marchex COO Peter Christothoulou spoke to ClickZ about another unique piece that Jingle brings to the deal.

“In the carrier world, because of the growth they’re experiencing in mobile device use, they’re seeing large growth in voice search. Jingle uniquely helps them by automating a lot of that experience.”

Marchex also believes that the opportunity for in-call advertising will continue to expand. Its internal analysis posits that with the addition of Jingle, call-driven revenues will represent more than 75 percent of revenues on an annualized basis by the end of 2011.

In the past year, Jingle Networks added Yellow Pages publisher Dex One as a distribution partner and acquired BlackBerry search provider Beyond 411, growing its mobile partner call volume by more than 200 percent.