According to an update at:
http://www.garyjohnson2012.com/front
Under “Governor Johnson’s Events”
“Gary Johnson will be a guest on NPR’s “Tell Me More” with host Michel Martin on Wednesday, June 20. Check local NPR listings.”
Live streaming audio is available at:
http://www.npr.org/player/v2/mediaPlayer.html?action=3&t=live1&islist=false
A podcast may also be available starting June 21st at:
http://www.npr.org/programs/tell-me-more/
Local affiliates and broadcast schedules may also be found at:
http://www.npr.org/templates/stations/stations/

A transcript of this interview is available here:
http://www.npr.org/2012/06/21/155504668/gary-johnson-offers-third-choice-in-2012-elections
The Podcast is available here:
http://www.npr.org/player/v2/mediaPlayer.html?action=1&t=1&islist=false&id=155504668&m=155504663