Bob Boilen hosted the show along with author of "The Beatles on Apple Records", Bruce Spizer. They historically recall these sessions with interesting facts like who mixed this and that such as Glynn Johns mix and then compared them to Phil Spector mixes of songs like Two of Us. Explaining Let it Be; Glynn John's mix with no horns was compared to the George Martin produced 45" single which the noticable difference was the added horns quietly in the background. Phil Spector's mix was the same recording of the George Martin version but the horns were brought up much louder. Also the de-Spectorized version of The Long and Winding Road was played and explained. Spizer explained that in the album and 45" versions, Spector actually stripped out Paul's vocal on the 2nd bridge "Many times I've been alone, and many times I've tried", and played the different versions.
A very worthwhile listen. Here is a link to the NPR site: All Songs Considered