I thought I'd post this as a general introduction to the topic for anyone who is interested in a quick overview ...
What is the 'Hare Krishna' movement?
The 'Hare Krishna' movement is officially known as ISKCON - 'The International Society for Krishna Consciousness', with its purpose being to spread Krishna consciousness around the world.
What is Krishna consciousness?
Krishna consciousness is an sublime process of self realisation which has existed for many thousands of years, especially within India. It has become increasing popular around the world since the 1960's when an elderly monk known as A.C. Bhaktivedanta Swami Prabhupada, on the order of his guru (Srila Bhaktisiddhanta Sarasvati Thakur) brought the teachings from India and single-handedly took the responsibility of spreading them around the Western world.
Krishna is a name for God which means 'all-attractive' - God has many names around the world such as Allah or Jehovah, just as the sun is also known by various names in the different languages of the world. Although different people around the world may describe the sun in varying ways with different languages we can easily understand that in truth it is the same sun which rises each morning in all parts of the globe. Similarly although God is given many different titles it is to be understood that as the Supreme Person He is above all sectarian notions of 'Religion' and it is the same God being worshipped by the majority of people around the planet.
This act of worshipping Krishna or God is identified in the ancient scriptures of India as 'sanatana-dharma', literally meaning 'eternal duty'. Swami Prabupada himself describes it as follows:
"Sanatana-dharma does not refer to any sectarian process of religion. It is the eternal function of the eternal living entities in relationship with the eternal Supreme Lord... Non-sanatana religious faith may have some beginning in the annals of human history, but there is no beginning to the history of sanatana-dharma because it remains eternally with the living entities."
The Primary role of the Krishna consciousness movement is to spread the process of mantra meditation (chanting/singing God's holy Names) around the world and to promote the understanding of 'sanatana dharma' as it is described in the ancient Vedic scriptures (such as Bhagavad-Gita, Srimad Bhagavatam & the Upanishads).
Specifically Hare Krishnas promote the use of the following 'Maha-matra' (Great mantra) but other names of God can also be used if one is already following a particular faith:
Hare Krishna Hare Krishna,
Krishna Krishna Hare Hare,
Hare Rama Hare Rama,
Rama Rama Hare Hare.
This mantra is from an ancient text called the Kali Santaran Upanishad which describes this mantra as being an especially effective prayer/mantra for making spiritual progress in this current age which is known as the 'age of Kali'.
The word 'Hare' refers to the energy of the Lord, and the words 'Krishna' and 'Rama' refer to the Lord Himself. The Maha-mantra has been well known in India ever since 500 years ago when a person known as 'Chaitanya Mahaprabhu' (also known as Gauranga) spread it publically around the country. This mantra can be spoken sofly to oneself, or can be sung by a group of people, depending on the circumstances. Most practitioners spend some time each morning in meditation, and then meet with others throughout the week.
Here's Srila Prabhupada's description of the Maha-mantra:
"Krishna consciousness is not an artificial imposition on the mind; this consciousness is the original energy of the living entity. When we hear the transcendental vibration, this consciousness is revived...This chanting of 'Hare Krishna, Hare Krishna, Krishna Krishna, Hare Hare / Hare Rama, Hare Rama, Rama Rama, Hare Hare' is directly enacted from the spiritual platform, and thus this sound vibration surpasses all lower strata of consciousness - namely sensual, mental, and intellectual...as such anyone can take part in the chanting without any previous qualification."
Hare Krishna,
...Neemai