"In summary, the walking process involves four stages: lifting, raising, shifting, and dropping. Your inhalation is coordinated with the lifting movement of the heel of your foot and your exhalation with keeping your foot lifted, while your toes are still touching the ground. Your inhalation is coordinated with the raising and shifting movements and your exhalation with the dropping of your foot. While you are coordinating your breath with your physical movements, remember to pay bare attention to what is taking place; avoid making judgments, decisions, or comments.
Observe the impermanent nature of your walking experience: the intention that precedes each movement, the movement itself, and every breath which rises and falls from moment-to-moment. When your mind shifts to another object of awareness, focus on seeing that it is also impermanent. Then, gently but firmly, place your attention back on your walking movements, coordinating them with your breath."
- Matthew Flickstein, Journey to the Center: A Meditation Workbook.
Boston, Wisdom Publications, 1998. pp.127-132.
I've added a number of new links to the webpage on Walking Meditation
Walking Meditation Resources
Cloud Hands Website