I won\'t use GIcon to change for the marker.Any other ways to change color of marker???
Nope, if you wan't to customize your marker, you will need to use GIcon.
You can find a whole lot of free markers at the Google Maps Icons Project. The code to use a custom marker is pretty straightforward:
// Create our "tiny" marker icon
var blueIcon = new GIcon(G_DEFAULT_ICON);
blueIcon.image = "http://gmaps-samples.googlecode.com/svn/trunk/markers/blue/blank.png";
// Set up our GMarkerOptions object
markerOptions = { icon:blueIcon };
// add the markerOptions as the second param to GMarker constructor
map.addOverlay(new GMarker(latlng, markerOptions));