This is an example of an avanced rollover using 'TellTarget' is given the movieclip name (instancename) and after that you tell it what to play(frames) and then boom it works! . Normal rollover is part of the button... and can be clicked on and can be clicked on as the button. Here the text that pops up is part of the button but cannot be clicked on at all.
Note : That was a vague explaination for better explaination ask for a tutorial or something
