Meditating regularly can benefit us in many ways, such as:
On a physical level - it can lower blood pressure, release stress and relax muscles
On a emotional level - it can boost your self confidence, reduce anxieties and fears and help you regain a balance in your life
On a mental level - it can help you to focus, foster a more flexible mind and alter set thinking patterns
On a spiritual level - it can help you to connect to your inner self, intuition and the resources and energy you have within
The reasons why someone meditates are just as numerous, for example:
Some meditate to help cope with life
Some to relax
Some to stem the flow of 'mind-chatter'
Some to find spiritual enlightenment
The ways people meditate are equally as numerous. Here are some examples:
Losing yourself in a task, hobby or view
Guided Meditations
Movement meditations (walking, dancing or tai chi)
Visualisations
Some of these are explored in our Guided Meditation CD 'Introducing Meditation'

The position you use to meditate is up to you.
The only criterion here is to be comfortable.
It doesn't matter why you meditate, just that you do meditate.