OIT has services that allow you to stream live or pre-recorded videos to password protected groups or to the world. 

Wowza allows you to stream live to desktop and mobile devices to broad, non-password protected audiences

Warpwire allows you to stream pre-recorded videos to password protected or non-password protected audiences as well as embed video in such applications as Sakai, Wordpress or the Duke Wiki

YouTube allows you to stream pre-recorded videos to non-password protected audiences and is best for marketing or material that is meant to be consumed by a large, public audience

Apple Podcasts allows you to publish your content to Apple Podcast users on iOS devices and AppleTVs. - note, we do not curate the site.