I did this to get rid of the overflow (scrollbar) ...
by the end of the jquery.fancybox....js file there are onStart, onCancel, onComplete etc. functions, and they are all empty ... so just go ahead and fill into the curly brackets of onStart with "$('body').css('overflow','hidden')" and onClosed "$('body').css('overflow','visible')" ... should look like this ...
onStart:function(){$('body').css('overflow','hidden')},
onClosed:function(){$('body').css('overflow','visible')},
peace