iTunes is the most common MP3 player on Apple Macintosh computers (and chances are your Apple Macintosh computer already has a copy installed). Here is astep-by-step for playing the MP3 CDs in your Apple Macintosh computer with the program iTunes:
Click here for directions if you're using a PC computer instead of an Apple Macintosh computer.
There are thousands of old time radio episodes at OTRCAT.com you can listen to online.