I'm new to smarty and wrox book did not cover enough on it. Before studying on it further my question is that for including smarty templating in my php sites, shall I keep/copy a common group smarty class files in each site I create and work with them in php script by including class files ? is it the mantra of working with smarty ?
Google PHP Autoload. I've found it helpful to create my own autoloader function with PHP5 that will include all the necessary Smarty classes. That way you don't have to manually include each file in your code. It makes the rest of your code cleaner as well. Check out the Smarty Quick Install guide. It should get you up and running.