If you don't mind another CDN, Microsoft seems to be hosting it: http://ajax.aspnetcdn.com/ajax/jquery/jquery-1.5.min.js (that domain is cookie-less too)
$ curl -I https://ajax.googleapis.com/ajax/libs/jquery/1.4.4/jquery.min.js
HTTP/1.1 200 OK
Content-Type: text/javascript; charset=UTF-8
Last-Modified: Mon, 15 Nov 2010 20:40:52 GMT
Date: Mon, 31 Jan 2011 20:03:57 GMT
Expires: Tue, 31 Jan 2012 20:03:57 GMT
Vary: Accept-Encoding
X-Content-Type-Options: nosniff
Server: sffe
Cache-Control: public, max-age=31536000
Age: 51530
Transfer-Encoding: chunkedFrom http://www.asp.net/ajaxlibrary/cdn.ashx#ajaxmicrosoftcom_ren...:
The CDN used to use the microsoft.com domain name and has been changed to use the aspnetcdn.com domain name. This change was made to increase performance because when a browser referenced the microsoft.com domain it would send any cookies from that domain across the wire with each request. By renaming to a domain name other than microsoft.com performance can be increased by as much to 25%. Note ajax.microsoft.com will continue to function but ajax.aspnetcdn.com is recommended.