Firstly let's skip the argument about what is and isn't a podcast, we'll do that some other time.  Call them what whatever you like, there is a plethora of good technical content out there, which sure beats the time we used to spend frantically searching compuserve at 9600 baud for Acorn Econet (and that's not a spelling mistake!) wiring diagrams. Listed below are a few of our favourite vidcast / netcast / podcasts :

• Technet Radio - Microsoft's very own audio offering.
• IT Idiots - Video based offering, covering a variety of Windows technologies.
• Windows Weekly - Paul Thurrott covers all things Microsoft.
• dnrTV - Carl Franklin and guests cover a wide variety of Microsoft technologies in glorious screencast goodness!