Can any one let me know the best site for start with Neural Networks?

Answer 1

Here's a few that I've looked through that have some good basic information and some other resources for more detailed information:

Back-Propagation Neural Network Tutorial
http://ieee.uow.edu.au/~daniel/software/libneural/BPN_tutorial/BPN_English/BPN_English/

Neural Networks in Plain English
http://www.ai-junkie.com/ann/evolved/nnt1.html

Introduction to Neural Networks
http://www.willamette.edu/~gorr/classes/cs449/intro.htm

Neural Network Theory - A short tutorial
http://documents.wolfram.com/applications/neuralnetworks/index2.html

Answer 2

http://en.wikipedia.org/wiki/Neural_network

Wikipedia-always the best place to start research.