jquery toggle slide from left to right and back

See this: Demo

$('#cat_icon,.panel_title').click(function () {
   $('#categories,#cat_icon').stop().slideToggle('slow');
});

Update : To slide from left to right: Demo2

Note: Second one uses jquery-ui also

Sliding from the right:

$('#example').animate({width:'toggle'},350);

Sliding to the left:

$('#example').toggle({ direction: "left" }, 1000);