TOOLS

Audacity
Audacity is a free, easy-to-use, multi-track audio editor and recorder for Windows, Mac OS X, GNU/Linux and other operating systems. The interface is translated into many languages. Audacity is free software, developed by a group of volunteers and distributed under the GNU General Public License (GPL).  FREE DOWNLOAD

REMOTE INTERVIEWS
If you are interviewing someone remotely then Skype is your friend. You’ll need an add-on to record the interview, and for that I recommend Total Recorder (for PC) or Call Recorder for Skype (for Mac).

USEFUL RESOURCES

Sound Cloud Extractor to MP3
How to publish Professional Podcasts