Looking to advertise on a podcast? Podtrac, the company that connects advertisers with podcasters, said Tuesday it will hold the first online advertising auction to determine ad rates for the podcasting market.

Advertising positions for three iTunes podcasts are being auctioned starting today. They include a technology podcast, "This Week in Technology," and entertainment podcasts MuggleCast and Josh & Japan. The online auction begins today and ends March 31.

Podtrac may have pushed a model for podcast advertising, but Google Inc. also appears interested in the market, according to Tim Bourquin, chief executive officer at TNC New Media, the creator of the Podcast & Portable Media Expo.

Google announced Tuesday it will acquire dMarc Broadcasting Inc. of Newport Beach, Calif. The search firm plans to create a new radio ad distribution channel by integrating dMarc's technology into Google's AdWords platform. dMarc assists broadcasters by automatically scheduling and placing advertising. dMarc creates an automated platform that lets advertisers more easily schedule and deliver ads via radio and keep track of air times. "I doubt Google is getting into radio advertising," Bourquin said. "I would bet they will use this technology to somehow deliver podcast advertising."

Google has already bought advertising in print publications and resold chunks of the space to its online advertisers.