What is meditation?
according to Wikipedia:
Meditation describes a state of concentrated attention on some object of thought or awareness. It usually involves turning the attention inward to a single point of reference. Meditation is often recognized as a component of eastern religions, where it has been practiced for over 5,000 years. Different meditative disciplines encompass a wide range of spiritual and/or psychophysical practices which can emphasize development of either a high degree of mental concentration, or the apparent converse, mental quiescence.
Why do we have to meditate?
Not only does meditation plays a big help in quieting the mind, it also helps treat and prevent heart disease, diabetes, arthritis, strokes and other diseases as well a blood pressure in people with hypertension.
I'm actually starting to meditate these days... and believe me... it does help. :)