Will you plz guide me to some reference material. As I have nothing done with flash except some minor animations.
Well, the process is quite simple. Not much experience required. Even simple gotoAndPlay(), gotoAndStop(), stop() functions could help you to make it. Here's a primer that will teach you to make a simple drop-down. http://www.kirupa.com/developer/mx/dropdownmenu.htm.
You could modify it your own way and get what you want.
Of course if you have a little more experience with flash and actionscript, you could make flexible and reusable menu with better features, that could be better animations or importing menu items from XML.