There are several ways to help from here in the United States, from CNN.
Italian Red Cross: To donate in English with the US dollar or other international currencies, use this fund set up by the International Federation of Red Cross and Red Crescent Societies (IFRC).
National Italian American Foundation (NIAF): The foundation is supporting rescue and long term relief operations.
Save The Children: The organization is working in Amatrice to create safe spaces and support for children.
More information can be found here.