This function creates Gmaps v3 bounds

gistfile1.js

function createBounds(list){
	var maxlat=null, maxlng=null, minlat=null, minlng=null;
            jQuery(list).each(function (index, elem) {
                try {
                    if (elem) {
                        var lt = parseFloat(elem.lat), lg = parseFloat(elem.lng);
                        if (lt != 0 || lg != 0 || !isNaN(lt) || !isNaN(lg)) {
                            maxlat = (maxlat==null)?lt:Math.max(maxlat, lt);
                            maxlng = (maxlng==null)?lg:Math.max(maxlng, lg);
                            minlat = (minlat==null)?lt:Math.min(minlat, lt);
                            minlng = (minlng==null)?lg:Math.min(minlng, lg);
                        }
                    }
                } catch (err) {
                    throw "ERROR! :" + err;
                }
            });             
	return new google.maps.LatLngBounds(new google.maps.LatLng(minlat,minlng), new  google.maps.LatLng(maxlat,maxlng));
}

The var list is an Array of JSON items with this structure:

hotels = [
{
lat: -33.85046783834696,
lng: 151.21843479573727,
name: "Hotel-1 Name",
catCode: "Cat3",
id: "123"
},
{
lat: -33.87100014835596,
lng: 151.22224990278482,
name: "Hotel-2 Name",
catCode: "Cat3",
id: "456"
}
];