When creating podcasts, you need the right tools to record interviews, use VoIP, it is great because you can record your conversations and interviews with others using software and edit it the way you want. Two great VoIP services are Skype and MagicJack. Just as a side note you can import your google contacts into Skype.
If you go with Skype, the program is installed on Windows, MAC and Linux. Once installed you can use something called Call Recorder to your Mac to record Skype sessions. It costs $25 or so. Another option is pamela, which is great for recording Skype conversations as well.
A program called Levelator is used to make both ends of the conversation be equal in volume.
To produce your podcast a ton of people use Audacity, it is free. Another option for Mac users is Garage Band.