var oMap = new GMap2(document.getElementById('googleMap'));
oMap.addControl(new GLargeMapControl);

var oOfficeLocation = new GLatLng(52.123753, 5.18544)
oMap.setCenter(oOfficeLocation, 12);

var sWindowContent = '<b>Adres:</b><p>Waterman 45<br />3721 WE Bilthoven</p>';
oMap.openInfoWindow(oMap.getCenter(), sWindowContent);