<script src="http://maps.google.com/maps?file=api
&amp;v=2&amp;key=[key]"
type="text/javascript"></script>
<script type="text/javascript">

//<![CDATA[

var map = null;
var geocoder = null;

function load() {
if (GBrowserIsCompatible()) {
map = new GMap2(document.getElementById("map"));
map.setCenter(new GLatLng(40.266044,-74.718479), 13);
geocoder = new GClientGeocoder();
map.addControl(new GSmallMapControl());
map.addControl(new GMapTypeControl());
}
}

function showAddress(address) {
if (geocoder) {
geocoder.getLatLng(
address,
function(point) {
if (!point) {
alert(address + " not found");
} else {
map.setCenter(point, 13);
var marker = new GMarker(point);
map.addOverlay(marker);
marker.openInfoWindowHtml(address);
}
}
);
}
}
//]]>
</script>

[...]

<form action="#"
onsubmit="showAddress(this.address.value);
return false">
<p><input type="text" size="60" name="address"
value=" 2751 Brunswick Pike, Lawrenceville, NJ 08648" />
<input type="submit" value="Go!" />
</p>
<div id="map" style="width: 500px; height: 300px"></div>
</form>