Last week the AJAX script files included for ASP.NET MVC applications were added to the AJAX content delivery network. The content delivery network is a free service that provides caching support for some of Microsoft's AJAX libraries. As a developer you benefit from a network by not having to host the files yourself. As a user you benefit from a network by having access to widespread local mirrors and cached access to script files across different sites you might visit.
The script locations to include for ASP.NET MVC 1 are:
Equivalent debug versions of the scripts are also available.