Edit in JSFiddle

$("#buscar").autocomplete({
    source: function(event, response){
        var datos = [
            {value: "Google", url: "http://www.google.com"},
            {value: "Bing", url: "http://www.bing.com"},
            {value: "Yahoo", url: "http://www.yahoo.com"}
        ];
        return response(datos);
    },
    select: function(event, object){
        window.open(object.item.url);
    }
});