bing.js

var road = new OpenLayers.Layer.Bing({
    name: "Road",
    key: apiKey,
    type: "Road"
});
var hybrid = new OpenLayers.Layer.Bing({
    name: "Hybrid",
    key: apiKey,
    type: "AerialWithLabels"
});
var aerial = new OpenLayers.Layer.Bing({
    name: "Aerial",
    key: apiKey,
    type: "Aerial"
});

map.addLayers([road, hybrid, aerial]);