Here are a couple podcasts introducing Windows developers to software development on the Macintosh.
Scott Hanselman: What’s it like for Mac Developers, an nterview with Steven Frank
.NET Rocks: Miguel de Icaza and Geoff Norton on Mono, mostly about .NET development on the Mac
Also, there are a lot of Mac-related talks on the GeekCruise podcast. The talks from January 2007 were directed at a general audience new to the Mac.
Hanselman’s podcast talks about some of the cultural difference between Microsoft and Apple customers. For example, Mac users update their OS more often and complain less about OS changes that break software.