From the Springfield Journal-Register: "Supreme Court Web site to feature audio, video of arguments," by Adriana Colindres--
Beginning next month, the Illinois Supreme Court will add a new feature to its Internet site: audio and video recordings of oral arguments in the cases it hears.
The court announced Friday that the arguments should be available on its Web site - www.state.il.us/court - the day after they take place, or possibly even sooner.
You can find more about the news in an Illinois Supreme Court press release (pdf). The audio will be available as MP3s; the video will be in Windows Media format. There will also be a podcast feed.
Several other courts already provide audio or video of oral arguments. You can find a list at the website for the law library at the University of Washington--scroll to the bottom of this page.