Free guided meditations from UCLA:
Each week has a different theme, and usually includes some introductory comments, a guided meditation, some silent practice time, and closing comments. Presented by the UCLA Mindful Awareness Research Center.
http://marc.ucla.edu/body.cfm?id=107
http://marc.ucla.edu/body.cfm?id=22
UCSD Center for Mindfulness:
Guided audio files for practicing Mindfulness-Based Stress Reduction (MBSR) from the UC San Diego Center for Mindfulness.
http://health.ucsd.edu/specialties/mindfulness/programs/mbsr/Pages/audio.aspx
Basic meditation with Tara Brach
Free meditations that you can stream or download.
https://www.tarabrach.com/guided-meditations/
Contemplative Mind in Society
Guided practices from Mirabai Bush, the center’s director, Diana Winston from UCLA’s Mindfulness Awareness Research Center, and Arthur Zajonc, president of the Mind & Life Institute.
http://www.contemplativemind.org/practices/recordings
Insight Meditation Society
Selected talks, podcasts, and audio streams, including various lengths of guided meditation.
http://www.dharma.org/resources/audio#guided
John Kabat Zinn on youtube: Professor of Medicine Emeritus and creator of the Stress Reduction Clinic and the Center for Mindfulness in Medicine, Health Care, and Society at the University of Massachusetts Medical School.
https://www.youtube.com/watch?v=8HYLyuJZKno