@Vikky, the beauty of responsive the different versions isn't really an issue any longer. That is always a problem with mobile. With responsive, the display changes depending on how wide your screen is. If you have your browser squeezed down to really narrow, it will show what the mobile device will see. If you maximize your window, it shows the full site.

I hear http://www.modernizr.com/ is good to help you manage this. On the Drupal side of things, I'm using Adaptive Theme. http://drupal.org/project/adaptivetheme