Nerd Podcasts on iTunes

 Weekly, I listed to:

Skeptoid (my favorite podcast)

Bagged and Boarded (great for hearing guest stars, retro stories and behind the scenes info)

Nerd Bastardcast (grat for keeping up on the latest nerd pop culture news)

The H.P. Lovecraft Literary Podcast (if you're a Cthulhu fan, this is the place for you.  This podcast always delivers)

SMODCast (Kevin Smith's signature podcast - usually pretty good)

The Joe Rogan Experience (Awesome podcast... great stuff, but very little nerd related.  It's just cool)

Kevin Smith also has 8 or 9 others... Tell Em' Steve Dave is another fun one.