If your a beginner/intermediate learner, the Japanese pod 101 series on itunes is good to listen to and its free. They update fairly frequently so there is a new one everyday or couple of days. They tend to alternate with a Japanese beginner lesson, then intermediate lesson then a blog said entirely in Japanese. You can still download a lot of the beginner lesson series on itunes.
I like them because in the lessons they play the conversations at natural speed, slow it down and then breakdown the grammar and vocab.