JQuery Cookie Plugin

Demo:

$.cookie('the_cookie'); // get cookie
$.cookie('the_cookie', 'the_value'); // set cookie
$.cookie('the_cookie', 'the_value', { expires: 7 }); // set cookie with an expiration date seven days in the future
$.cookie('the_cookie', '', { expires: -1 }); // delete cookie
$.cookie('the_cookie', null); // delete cookie
$.cookie(’the_cookie’, ‘the_value’, {expires: 7, path: ‘/’, domain: ‘jquery.com’, secure: true});

http://dev.jquery.com/browser/trunk/plugins/cookie/