I done a lot research but can't find the way to create latlng in the google map as below, how can I use address for the latlng number?

script

function initialize()
{
    var latlng = new google.maps.LatLng(-41.251290,174.803638);
    var opt =
    { 
        center:latlng,
        zoom:10,
        mapTypeId: google.maps.MapTypeId.ROADMAP,
        disableAutoPan:false,
        navigationControl:true,
        navigationControlOptions: {style:google.maps.NavigationControlStyle.SMALL },
        mapTypeControl:true,
        mapTypeControlOptions: {style:google.maps.MapTypeControlStyle.DROPDOWN_MENU}
    };
    var map = new google.maps.Map(document.getElementById("map"),opt);
    var marker= new google.maps.Marker({
    position: new google.maps.LatLng(-41.251290,174.803638),
    title: "CodeGlobe",
    clickable: true,
    map: map
});

çok teşekkürler!