Meditation takes many forms, sometimes incorporating music, yoga positions, or even hypnosis. And while often used in the West as a means of stress reduction, Eastern meditation practices go beyond that simple goal and provide practitioners with a means of achieving a higher state of existence, and insight into the nature of the universe.
Transcendental meditation gained popularity in the West in the sixties, bringing elements of ancient Vedic practices to the masses outside of India by His Holiness Maharishi Mahesh Yogi. Many scientific studies have been done regarding transcendental meditation, showing it to be effective in reducing stress and promoting good health, as well as inspiring creativity and intelligence.
Other types of meditation have been used for thousands of years. Meditation techniques dating back to the time of Lord Buddha have a highly spiritual basis, and although stress reduction and relaxation is one benefit, Buddhist meditation is used as an aid to achieve insight and assist one in achieving incrementally higher states of existence. Vipassana meditation, or insight meditation, focuses on a practice of mindfulness as a means of promoting calmness. These practices, and in fact most older meditation practices, do not use the tool of a repeating mantra, but instead allow the mind to flow naturally as it becomes increasingly aware, or mindful, of all things.
Zen and other Buddhist meditation practices focus on achieving mindfulness and refining the quality of one's awareness of all things, as opposed to striving to be aware of only a single word mantra. The mindfulness results in a heightened sense of awareness, while at the same time promoting a sense of acceptance and realization of all things, pleasant and unpleasant, as part of life.
Although it is certainly possible to teach oneself meditation, a meditation teacher, or at least a meditation CD or online meditation self-help site, may be very useful when getting started. And although meditation is part of an entire way of life and philosophy, you don't have to be knowledgeable in this philosophy, or even be a Buddhist at all to learn how to do it and realize its benefits. Although we tend to associate meditation with Eastern religions, in fact Christianity has various forms of meditation as well, although different terminology is used.
A guided meditation uses a teacher, or in some cases an audio recording, to assist the meditator in achieving a meditative state through a combination of words and music.
Although there are a great many tools and accoutrements available to assist in the meditative process, no tools are necessary at all. Many meditative practices even allow for meditation while walking, working, or even doing housework. Nonetheless, various tools such as a meditation chair, bench or cushion, special loose clothing, and other supplies may work well to promote comfort and lessen distractions so that the meditator can focus more on the goal at hand. Zen Buddhist meditation is a little more formal in its approach, and the position of the body takes on great importance. Typically, a person practicing Zen meditation will sit in a lotus, half lotus, or Burmese position, with hands folded in a mudra with one hand facing palm up and holding the other. This too, focuses on the samadhi, or mindfulness, to promote greater awareness.