Here are my recommendations on some great podcasts.
For listening to podcasts, I highly recommend Marco Arment's Overcast.
The public broadcasters in Canada, the UK, and Australia (CBC, BBC, and ABC) put a lot of fantastic shows online.
Science:
Quirks and Quarks (CBC)
The Science Show (ABC)
Science Friday (NPR)
All in the Mind (ABC)
Science In Action (BBC World Service)
Technology:
This week in Tech (TWIT.tv)
Security Now (TWIT.tv)
Mac Break Weekly (TWIT.tv)
Click (BBC)
Society:
In our Time (BBC)
Ideas (CBC)
Thinking Allowed (BBC)
Under the Influence (CBC)
This American Life (NPR)
Technology & Culture:
Current Events:
Background Briefing (ABC)
The House (CBC)
Misc: