Podcast measurement and ad firm Podbridge has launched an advertising network that will include inventory from large publishers, including BBC and Clear Channel radio, writes ClickZ. Podbridge will serve audio ads to podcasts in its network and track them. Most ads will be :15 or less and can be placed within or before or after the podcast. Its technology inserts ads dynamically, so new ads are inserted at the time of download - and can be updated/replaced each time a user synchs an iPod. Podcast and ad Playback data are uploaded to Podbridge's server at each synch.

For the most part, ads will be sold on a CPM basis, based on downloads or listens, with an occasional sponsorship of premium content. Targeting is available by age, gender, location and podcast content.

Ads will be sold through an exclusive relationship with online ad rep firm Ronning Lipset Radio, which also sells ads for Yahoo's Launchcast, AOL Radio, Live365 Radio, Clear Channel Radio and MSN Radio.