I love listening to podcasts on long drives to my locations.  Here are some of my favorites:

1.  The Landscape Photography Podcast – Hosted by Nick Page.
2. F Stop Collaborate & Listen – Hosted by Matt Payne.
3. Tripod – Part of the Improve Photography Podcast series.  It’s a bit harder to get to now that Jim Harmer lumped them all into the Improv Photography stream, but still worth listening to whenever they post new episodes…which have been few and far between lately.
4.  Photog Adventures – A relatively new landscape photography podcast hosted by Brendon Porter and Aaron King.
5. Lens & Landscape –  Another very informative landscape photography podcast hosted by Fred Weymouth.  
6. Improve Photography – This podcast has a huge following on Facebook with close to 700,000 followers.  Hosted by Jim Harmer, this podcast covers a wide range of topics.  Tripod (above) is an offshoot of Improve Photography.
7. This Week In Photo – One of the first, if not THE first photography podcast.  I believe this podcast was an offshoot of This Week In Tech hosted by Leo Laporte.  This particular podcast is skewed more towards industry news and less toward useful techniques, gear reviews, etc.