Prova a fare così:
file "mappa.htm"
codice:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<META http-equiv=Content-Type content="text/html; charset=windows-1252">
<SCRIPT src="js/jquery-1.2.6.js" 
type=text/javascript></SCRIPT>

<SCRIPT src="js/maps" type=text/javascript></SCRIPT>

<SCRIPT type=text/javascript charset=utf-8>
		$(document).ready(function(){ //Start script when ready
			if (document.getElementById("map_canvas")) {//Checks to see that the page element exists and to prevent conflict with other maps
				
				//Default map center location
				var defaultLat = 50.5;
				var defaultLon = -1.4;
				
				var markers = new Array();
                markers[0] = new Array(new GMarker(new GLatLng(12.345678,12.345678)), "Prima indicazione", "Qui ci puoi mettere
L'indirizzo e se vuoi
altre indicazioni
 altre cose che vuoi tu");
                markers[1] = new Array(new GMarker(new GLatLng(13.345678,12.345679)), "Seconda indicazione", "Qui ci puoi mettere
L'indirizzo e se vuoi
altre indicazioni
 altre cose che vuoi tu");

				var map = new google.maps.Map2($("#map_canvas").get(0));//Initialise google maps
				map.setCenter(new GLatLng(defaultLat, defaultLon), 8);//Set location to the default and zoom level to 8
				map.disableDoubleClickZoom();//Disable zooming

				
				$.each(markers,function(i,marker){
					var delayTime = ((i * 3000) / (0.5 * markers.length));//Delay time decreases as number of markers increases
				
					setTimeout(function(){ 
						map.addOverlay(marker[0]);
						$("<li />")
							.html(markers[i][1])//Use list item label from array
							.click(function(){
								displayPoint(marker[0], i);
								setActive(this);//Show active state
							})
							.appendTo("#map_list");
					
						GEvent.addListener(marker[0], "click", function(){
							displayPoint(marker[0], i);
							setActive(i);//Show active location
						});
						
						displayPoint(marker[0], i);
						setActive(i);//Show active location
						if (i == (markers.length - 1)) {//If last item in array
							setTimeout(function(){//Remove active class and fade marker after delay
								$("#map_message").fadeOut();
								//setActive();
							}, 3500);
						}
					}, delayTime); 
				});
				
				$("#map_list").css("opacity","0.2").animate({opacity: 1}, 1100);//Fade in menu
				$("#map_message").appendTo(map.getPane(G_MAP_FLOAT_SHADOW_PANE));
								
				function displayPoint(marker, index){
					if ($('#map_message').is(':hidden')) {//Allow toggling of markers
						$('#map_message').fadeIn();
					}
					else{//Remove all .active classes and hide markers
						$('#map_message').hide();
						$(".active").removeClass();
					}
					//$("#map_message").hide();//Default behaviour, doesn't allow toggling
					
					var moveEnd = GEvent.addListener(map, "moveend", function(){
						var markerOffset = map.fromLatLngToDivPixel(marker.getLatLng());
						$("#map_message")
							.html(markers[index][2])//Use information from array
							.fadeIn()
							.css({ top:markerOffset.y, left:markerOffset.x });
					GEvent.removeListener(moveEnd);
					});
					map.panTo(marker.getLatLng());
				}	
				
				function setActive(el){
					$(".active").removeClass();//Remove all .active classes
					$("#map_list").find('li').eq(el).addClass('active');//Find list element equal to index number and set active
					$(el).addClass('active');//Set active if list element clicked directly
				}
			}//End if map_canvas exists
		}); //End onReady
		</SCRIPT>

<STYLE type=text/css media=screen>.map {
	BORDER-RIGHT: 0px; PADDING-RIGHT: 0px; BORDER-TOP: 0px; PADDING-LEFT: 0px; PADDING-BOTTOM: 0px; MARGIN: 0px; BORDER-LEFT: 0px; WIDTH: 800px; PADDING-TOP: 0px; BORDER-BOTTOM: 0px; HEIGHT: 500px
}
#map_canvas {
	FLOAT: left
}
#map_list {
	PADDING-RIGHT: 0px; PADDING-LEFT: 0px; BACKGROUND: #ebebeb; FLOAT: left; PADDING-BOTTOM: 0px; MARGIN: 0px; WIDTH: 150px; PADDING-TOP: 0px; LIST-STYLE-TYPE: none; HEIGHT: 500px
}
#map_list LI {
	PADDING-RIGHT: 0.5em; PADDING-LEFT: 0.5em; PADDING-BOTTOM: 0.5em; PADDING-TOP: 0.5em
}
#map_list LI:hover {
	BACKGROUND: #555; CURSOR: hand; COLOR: #fff
}
#map_list LI.active {
	BACKGROUND: #555; COLOR: #fff
}
#map_list LI.active:hover {
	BACKGROUND: #363636; CURSOR: default
}
#map_message {
	PADDING-RIGHT: 0.5em; DISPLAY: none; PADDING-LEFT: 0.5em; FONT-SIZE: 0.9em; BACKGROUND: #555; PADDING-BOTTOM: 0.5em; WIDTH: 12em; COLOR: #fff; PADDING-TOP: 0.5em; POSITION: absolute
}
#map_message IMG {
	BORDER-RIGHT: 0px; BORDER-TOP: 0px; MARGIN-TOP: 0px; BORDER-LEFT: 0px; BORDER-BOTTOM: 0px
}
#map_message A {
	COLOR: #caeaf9; BORDER-BOTTOM: #ebebeb 1px solid
}
#map_message A:hover {
	COLOR: #fff; BORDER-BOTTOM: #caeaf9 1px solid
}
</STYLE>
<!--[if IE 7]>
<META content="MSHTML 6.00.6000.16850" name=GENERATOR></HEAD>
<BODY>
<style>
#map_list li{
width: 100%;
zoom: 1;
float: left;
}
</style>
<![endif]--> 
<DIV class=map id=map_canvas></DIV>
<UL class=map_list id=map_list>[/list]
<DIV id=map_message></DIV></BODY></HTML>
Allo stesso livello del file "mappa.htm" crea una cartella di nome "js" e al suo interno mettici i file: jquery-1.2.6.js e maps
che puoi scaricarti direttamente dal link da te postato

http://www.erikwhite.net/gmapjquery.html

semplicemente facendo:
File
salva con nome...
poi dalla casella: Salva come,
seleziona: pagina web completa (*.htm, *.html)
scegli un nome da dare o lascia quello proposto e salvalo dove vuoi.
ti verrà salvata assieme alla pagina una cartella che al suo interno contiene i due file. Copiali e incollali nella tua cartella "js"
fai doppio clik sulla pagina mappa.htm e vedrai che funziona.