Where can I get proper rules of the games in darts

Go to a good toy shop.
Buy a dart board and darts package.
There is usually a rules book in the package.

This should help for starters: Darts - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Darts)
Also it really depnds on what style of game you are thinking of playing as there are several as detailed here: http://www.darting.com/Dart_Rules-c1121-wp1195.htm