How to pass parameters to a JQuery $.getJSON callback method?

Pass them as an object just after the URL and before the function:

function CallMethod() {
     $.getJSON('/website/RESTfulService.svc/LiveLocation/json', 
     {
        x: "1",
        y: "2"
     }, 
     function(data) {
         getResult(data.lat, data.lon);
     });
}