Online audio content provider Audible.com is unveiling AudibleWordcast at the Podcasting & Portable Media Expo in Ontario, Canada today. Wordcast will allow podcast creators to monetize their shows by giving them access to ad opportunities, sponsorships and underwriting. To handle the question of measurement - an important component that's always been up in the air when it comes to podcasts - Audible will use ImServices Group, a media auditing firm. ImServices will make sure that the numbers are accurate and take into account not just downloads but also subscribers.