An easy and cheap (free) way to record a podcast or Skype call into separate tracks using your mac.

Skype:
https://www.skype.com/en/download-skype/skype-for-computer/

Soundflower:
https://github.com/mattingalls/Soundflower/releases

LineIn:
https://www.macupdate.com/app/mac/11333/linein

Check out my music photography podcast here:
www.bigpantsphoto.com/podcast