If you don't have itunes already, you might consider getting it. Download this audio program free here:
Once you have itunes, you can go to the "itunes store" and search for free podcasts. I recommend podcasts from NPR (search for "NPR" and many podcasts will show up; almost all will be free. You'll be able to tell which are and which aren't free). Also, if you would like to listen to good short stories, search for "New Yorker" and subscribe to the "New Yorker: Fiction" podcast. These 20 -30 minute pieces consist of someone reading a short story and then two people discussing the story.
You can also search for "ESL" or other podcasts for learning English. Many of them will be free.
(Note: if you "subscribe" to a podcast, it means your computer will automatically download each new podcast in that series. You can always unsubscribe or delete the podcasts. You can listen to podcasts on your computer or on an MP3 player (an ipod).)