The New Age movement is an umbrella term for any number of different beliefs, ideas and lifestyles.  It has no single (human) leader, no organisation, no headquarters.  

Caryl Matrisciana who was a New Age person for many years and became a Christian gives a very good insight into it with her recipe for New Ageism:

2 cups of hope (carefully sift out all fear)

2 cups of altered consciousness (Yoga, drugs or meditation to taste)

3 tablespoons each of self-awareness, self-improvement & self esteem (melt away anything negative)

1 heaped teaspoon of peace,  1 large dollop of love,  1 handful of holism

1 generous pinch each of humanism, Eastern mysticism (Hinduism & Buddhism) and occultism

1 scoop of mystical experience

Mix thoroughly together.  Bake in a warm, friendly environment.  Fill with your most appealing dreams.  Garnish generously with positive thoughts and good vibrations.

The Apostle John speaks of the spirit of antichrist being already at work in the world in his day (1 John 4v2-3).  "Anti" means both "against" and "in place of."   New Ageism is not necessarily directly opposed to Christ, indeed He is often regarded as one of the gurus (what an insult), however every single thing they believe effectively replaces Christ, therefore it is of that spirit.  We as Christians can hopefully see this quite clearly but we also need to understand that most New Agers are genuine seekers after spiritual things.  They are therefore more open than many materialistic people to spiritual truth, but at the same time are deceived by the spirit of antichrist.

According to New Age people we are now living in the "Age of Aquarius" which is symbolised by the rainbow. According to New Age philosophy the Age of Aquarius will last 2,000 years and will be an era of spirituality, and of world harmony.  It replaces the "Age of Pices" which has lasted 2,000 years and is symbolised by the sign of the fish – the symbol of Christianity. During the last 2,000 years materialism and science have flourished but have only produced inequality and a devastated planet (hence the emphasis on ecology and an alternative spirituality to Christianity in New Age).