Tim Mitchell is a business intelligence consultant, author, trainer, and SQL Server MVP with over a decade of data management experience. He is a partner with Linchpin People and is the principal of Tyleris Data Solutions.
Tim has spoken at international and local events including the SQL PASS Summit, SQLBits, SQL Connections, along with dozens of tech fests, code camps, and SQL Saturday events. He is coauthor of the book SSIS Design Patterns, and is a contributing author on MVP Deep Dives 2.
Hanselminutes (http://www.hanselminutes.com) - This is a (mostly) weekly show that focuses on the expertise of Scott Hanselman. The tagline of the show calls Scott a 'technologist', which is a very humble term, in my opinion; he strikes me as the guy who knows almost everything about almost everything. This show is generally focused around .NET programming, but delves into other areas of technology. If you only listen to one podcast per week, make sure it's this one.
DotNetRocks (http://www.dotnetrocks.com) - This weekly show, hosted by programming veterans Carl Franklin and Richard Campbell, encompasses a wide variety of .NET programming topics. Their guest list reads like a whos-who of programming excellence, and the material covered is both broad and deep.
ASP.NET Podcast (http://www.aspnetpodcast.com) - This is a good program geared toward ASP.NET developers, and is hosted by Wally McClure. Although the show has had some audio problems in the past, the content is solid.
SQL Down Under (http://www.sqldownunder.com) - As the name suggests, this is a SQL Server broadcast based in Australia. This is the best SQL Server-specific podcast that I have found, and it does not disappoint. Their guests have included the likes of Kimberly Tripp, Adam Machanic, and Kalen Delaney.
SQL Server WorldWide Users Group Podcasts (http://www.sswug.org/sswugradio) - This repository hosts audio content from the SSWUG staff and others. The What's Happening broadcasts by Stephen Wynkoop are weekly publications of news and events in the SQL world; this is a useful download, but you must listen closely as Stephen talks very fast. Some of the audio here requires a paid membership in SSWUG.
If you have not checked out the above audio programs, do yourself a favor and listen in sometime.