All resources listed here are available for free.
Mindfulness Awareness Research Center at UCLA
Dan Siegel, PsyD: The Mindfulness Solution - Download Meditations
Chris Walsh, MD (Australian psychiatrist) [http://www.mindfulness.org.au]
Portland Psychotherapy - ACT Exercises and Audio Files
Portland Psychotherapy: Lovingkindness meditation
Association for Contextual Behavioral Science - Free audio exercises
Mindfulness Coach (for iPhone)
Guided imagery: You can also find some mindfulness-based recordings here.
Timers (for timing meditation periods)
Mindfulness Bell (webpage based programmable chime)
ProdMe (a programmable widget timer for Macs)
By Kristen Neff, PhD (Self-Compassion.org): Guided meditations for facilitating self-compassion
Affectionate Breathing (21 minutes)
Compassionate Body Scan (24 minutes)
Loving-Kindness Meditation (21 minutes)
Self-Compassion/Loving-Kindness Meditation (20 minutes)
Noting Your Emotions (20 minutes)
Soften, soothe, allow: Working with emotions in the body (16 minutes)
Sitting Together: Essential Skills for Mindfulness-Based Psychotherapy, by Susan M. Pollak, Thomas Pedulla, & Ronald D. Siegel. Note: This book is intended for psychotherapists, but their website has very good guided meditations in written and recorded form.