Mindfulness in Plain English by Bhante Gunaratana. A great introduction to meditation practice by a very experienced Sri Lankan monk practitioner and scholar. The title says it all.
Seeking The Heart of Wisdom by Joseph Goldstein and Jack Kornfield. A helpful introduction to insight meditation by two of the main Western teachers of this practice.
Loving Kindness: The Revolutionary Art of Happiness by Sharon Salzberg. An excellent introduction to metta practice and other heart practices of meditation, with great teaching stories by one of the founders of Insight Meditation Society.
Who Is My Self? by Ayya Khema. A clear introduction to concentration practice (jhanas) in a down to earth way. Written by a German Buddhist nun who spent a lot of time practicing in Sri Lanka.
When Things Fall Apart by Pema Chodron. An excellent book when you or a friend are going through a hard time. Good pithy dharma advice by an American Buddhist nun in the Tibetan tradition.
In The Words of the Buddha translated by Bhikkhu Bodhi. An introduction to the direct teachings and stories of the Buddha (the suttas) through the translation of an eminent American scholar/monk. If you like this you can move on to reading the sources from which this book is excerpted.
The Noble Eightfold Path by Bhikkhu Bodhi. A succinct introduction to the main teachings of the Buddha, including mindfulness Can be found online as well.
Eight Mindful Steps to Happiness by Bhante Gunaratana. Another excellent summary of the eightfold path.
Wherever You Go, There You Are by Jon Kabat-Zinn. Secular teacher of mindfulness meditation explains practices.
Weekly Meditation groups in the Bay Area led by Spirit Rock Teachers
Spirit Rock Meditation Center Marin County, CA
East Bay Meditation Center, Oakland, CA
Insight Meditation Center, Redwood City, CA
Insight Meditation Society, Barre, MA
Aranya Bodhi Hermitage & Dhammadharini Vihara (Women’s Monastic Community in No. CA)
Cambridge Insight Meditation Center, Cambridge, MA
List of meditation groups around the US from Buddhist Insight Network