Cross-domain ajax php proxy

The goal of this project is to create: 1. An A-Z menu using jQuery tabs 2. On clicking a tab, a web service is called via ajax and a cross-domain PHP proxy script and loads a list of items beginning with the selected letter into the main content area 3. On clicking an item from the loaded list, the content area is again replaced with the clicked link's content, again called via ajax through the proxy So I need. 1. A simple PHP webpage with an A-Z jQuery tabs menu and a main content area 2. A PHP script to call a web service (this is an RESTful API I have access to and returns XML or HTML) 3. The relevant AJAX/Javascript to update the main PHP page based on the selected tab/link