There are many models of alternative education. Under the umbrella of democratic education, each school is unique, with its own character, systems and vision. Some of these resources have helped us a lot in understanding how different models work.
The Summerhill School founded by A. S. Neill in 1921 in England, is the original alternative school. "Summerhill is the oldest children's democracy in the world. It is probably the most famous alternative or 'free' school. The system that Summerhill employs is not only about education - it is also a different way of parenting which eliminates most of the friction and many of the problems experienced by modern families."
The Summerhill Movie (1hr 48m) is a fantastic introduction to how an ideal democratic school operates.
Sudbury Valley School based in the United States in 1968 has been a model that has been replicated many times over. There are lots of books and videos about Sudbury Valley. Free at Last by Daniel Greenberg is a wonderful introduction to the Sudbury Valley World.
Note: Free at Last is available as paperback in India via the Banyan Tree Bookstore for Rs 300. We highly recommend reading this!
Books by John Holt
John Holt is considered the father of homeschooling. His books go deep into what actually happens inside a classroom (spoiler: everything but the subject matter being taught). He then goes deep into how children perceive the world and why classroom education model is a failure. His How Children Fail is an instant classic. Read 10 pages and you will change your life's persective!
IDEC / InDec (Indian Democratic Edcuation Conferenece) and Learning Soscieties Unconference (LSUC) are great ways to meet the alternative education community in India