jQuery n00b question. Need help for project ASAP!

jQuery n00b question. Need help for project ASAP!

$(function() {   
    $('#slider').hover(function() {
        $(this).children('li').stop().animate({
            left: '-652'
        }, 1000);
    }, function() {
        $(this).children('li').stop().animate({
        left: '0'
        }, 1000);
    });
});

When the user hovers over the image I want the image to slide to the left -652px, when they hover off it resets back to 0. What am I doing wrong?