You can use the fitBounds method for this.
a) create a bounds object: var bounds = new
google.maps.LatLngBounds();
b) each time you place a new marker (polyline/polygon, circle/
rectangle overlay etc). extend the bounds object by its lat,lng.;e.g.
var markerLatLng = new google.maps.LatLng
> I wanting to know though if I can set the map to centre automatically
> over the place marks?
Make a bounds object.
As each marker is created, extend the bounds to include it.
When all markers are processed, fit the map to the bounds.
As per
http://groups.google.com/group/google-maps-js-api-v3/b
