Mindfulness
Mindfulness might best be described as a 'way of being' rather than a technique, but in psychological terms it can be taught as a technique to increase insight and alter our relationship with our thoughts.
Free handouts
Mindful Attention Awareness Scale (MAAS) 
Download from Rochester.edu (0.1MB) | Link to MAAS page at Rochester.edu
Mindfulness Instructions - Instructions for teaching mindfulness 
Download from Mindfulness.org.au PDF (0.1MB)
Urge Surfing - Instructions for teaching clients how to 'urge surf' Download from Mindfulness.org.au PDF (0.1MB)
'Just worrying' - Instructions for teaching the 'just worrying' thought labelling technique Download from Mindfulness.org.au PDF (0.1MB)
Mindfulness handout Download from getselfhelp.co.uk
Body scan mindfulness exercise Download from Stillmind.com.au
Free mindfulness audio recordings
There are many packages of mindfulness recordings that can be bought, John Kabat Zinn in particular has produced a number that are suitable for recommending to clients.
Free Buddhist Audio is a website set up by the Triratna Buddhist Order. They make recordings of meditations, and Buddhist teachings available for free. Of particular interest to therapists might be:
Bells for meditation recording for those more advanced with meditation practice
General Links
Bangor Centre for Mindfulness Research and Practice
Mindfulness.org.au - Useful site on Mindfulness run by Dr Chris Walsh
Research papers
Download papers from Segal, Williams & Teasdale at MBCT.com
Baer, Ruth A. (2003) Mindfulness training as a clinical intervention: A conceptual and empirical review. Clinical Psychology: Science and Practice, 10(2), 125-143.
Buchheld N, Grossman P, Walach H (2001)Measuring mindfulness in insight meditation (vipassana) and meditation-based psychotherapy: The development of the Freiburg Mindfulness Inventory (FMI).Journal for Meditation and Meditation Research, 1: 11-34.