Plain Code

$.fn.fuckingAwesome = function( options ) {
    var self = this,
        win = $( window );
    options = $.extend( { min: 0 }, options );
    if ( options.min === "auto" ) { options.min = self.offset().top; }
    win.bind( "scroll resize", function() {
        var windowTop = win.scrollTop(),
            currentTop = self.offset().top;
        
        if ( windowTop > options.min || currentTop > options.min ) {
            var top = Math.max( windowTop, options.min );
            if ( options.max ) {
                top = Math.min( top, $.isFunction(options.max) ? options.max() : options.max );
            }
            self.stop().animate({
                top: top
            }, 200);
        }
    });
};