$('#timeline').mousedown(function(event){
    $(this).css({
		cursor: 'grabbing',
		cursor: '-moz-grabbing'
	}).data('down', true).data('x', event.clientX).data('scrollLeft', this.scrollLeft);
    return false;
}).mouseup(function(event){
    $(this).css({
		cursor: 'grab',
		cursor: '-moz-grab'
	}).data('down', false);
}).mousemove(function(event){
    if ($(this).data('down') == true) {
        this.scrollLeft = $(this).data('scrollLeft') + $(this).data('x') - event.clientX;
		//this.scrollLeft = $(this).data('scrollLeft') + ($(this).data('x') - event.clientX) * 2; // twice as fast
    }
}).mousewheel(function(event, delta){
    this.scrollLeft -= (delta * 30);
	return false;
}).css({
		overflow: 'hidden',
		cursor: 'grab',
		cursor: '-moz-grab',
	});
});

$(window).mouseout(function(event){
if ($('#timeline').data('down')) {
    try {
        if (event.originalTarget.nodeName == 'BODY' || event.originalTarget.nodeName == 'HTML') {
            $('#timeline').data('down', false);
        }
    } 
    catch (e) {
    }
}

$('#timeline').mousedown(function(event){
    $(this).css({
		cursor: 'grabbing',
		cursor: '-moz-grabbing'
	}).data('down', true).data('x', event.clientX).data('scrollLeft', this.scrollLeft);
    return false;
}).mouseup(function(event){
    $(this).css({
		cursor: 'grab',
		cursor: '-moz-grab'
	}).data('down', false);
}).mousemove(function(event){
    if ($(this).data('down') == true) {
        this.scrollLeft = $(this).data('scrollLeft') + $(this).data('x') - event.clientX;
		//this.scrollLeft = $(this).data('scrollLeft') + ($(this).data('x') - event.clientX) * 2; // twice as fast
    }
}).mousewheel(function(event, delta){
    this.scrollLeft -= (delta * 30);
	return false;
}).css({
		overflow: 'hidden',
		cursor: 'grab',
		cursor: '-moz-grab',
	});
});

$(window).mouseout(function(event){
if ($('#timeline').data('down')) {
    try {
        if (event.originalTarget.nodeName == 'BODY' || event.originalTarget.nodeName == 'HTML') {
            $('#timeline').data('down', false);
        }
    } 
    catch (e) {
    }
}
});

$('#timeline').mousedown(function(event){
                    $(this).css({
						cursor: 'grabbing',
						cursor: '-moz-grabbing'
					}).data('down', true).data('x', event.clientX).data('scrollLeft', this.scrollLeft);
                    return false;
                }).mouseup(function(event){
                    $(this).css({
						cursor: 'grab',
						cursor: '-moz-grab'
					}).data('down', false);
                }).mousemove(function(event){
                    if ($(this).data('down') == true) {
                        this.scrollLeft = $(this).data('scrollLeft') + $(this).data('x') - event.clientX;
						//this.scrollLeft = $(this).data('scrollLeft') + ($(this).data('x') - event.clientX) * 2; // twice as fast
                    }
                }).mousewheel(function(event, delta){
                    this.scrollLeft -= (delta * 30);
					return false;
                }).css({
						overflow: 'hidden',
						cursor: 'grab',
						cursor: '-moz-grab',
					});
            });
            
            $(window).mouseout(function(event){
                if ($('#timeline').data('down')) {
                    try {
                        if (event.originalTarget.nodeName == 'BODY' || event.originalTarget.nodeName == 'HTML') {
                            $('#timeline').data('down', false);
                        }
                    } 
                    catch (e) {
                    }
                }
            });

http://jqueryfordesigners.com/fun-with-overflows/

Modified the code very slightly to add in cursor states for when the timeline is grabbed. Also added in (but commented out) the code to make the sliding twice as fast using a multiplier.

jQuery Overflow Timeline Effect

plugin, jquery

jQuery