I just found this on the Microsoft Events and Webcasts website. You can now download podcasts of our popular webcast series in either WMA or MP3 format. There are a variety of topics for IT pros's including Active Directory, Exchange Server, Office System, SQL Server 2005, Windows Vista and Scripting.
You can also add each section as an RSS feed to you never miss out on that important podcast! So if you're planning on hitting the gym why not bring along your favourite MP3 player and listen to a Microsoft podcast!
I found these a little while ago and have since added the RSS feed into Outlook 2007 - the Vista presentations by Kevin Remde (http://blogs.technet.com/KevinRemde/) can be highly recommended.