403禁止JSONP请求

There is a domain I don't control which returns JSON data -- going to http://services.example.com/search?store=ITUNES&q=twitter yields something like

{
  MySearch: {
    resultCount: 1
    results: [
      { name: "twitter" }
    ]
  }
}

When I try to get it with jsonp from another domain, such as from my own computer (using jQuery) --

$.ajax({
    url: 'http://services.example.com/search?store=ITUNES&q=twitter',
    dataType: 'jsonp',
    success: function(data) {
        console.log('hi');
    }
});

I get "Status Code: 403 Forbidden".

Here are the server response headers:

Connection:keep-alive
Content-Length:9
Content-Type:text/plain
Date:Thu, 05 Jan 2012 20:33:04 GMT
Server:WEBrick/1.3.1 (Ruby/1.9.3/2011-10-30)
X-Frame-Options:sameorigin

Is there any way I can get this data without making any server-side changes?