Adding labels to OL

//create a style object
var style = new OpenLayers.Style();
//rule used for all polygons
var rule_acres = new OpenLayers.Rule({
symbolizer: {
    fillColor: "#ff9a9a",
    fillOpacity: 0.5,
    strokeColor: "#000000",
    strokeWidth: 1,
    strokeDashstyle: "dash",
    label: "${acres}",
    labelAlign: "cc",
    fontColor: "#333333",
    fontOpacity: 0.9,
    fontFamily: "Arial",
    fontSize: 14}
});
style.addRules([rule_acres]);