Now it's working :)

The problem now is that I have a list called 'Lista Diccionario'
and I want to get all the items there.

"There's the code" but it doesn't work.

look:

    var _listName = "Lista Diccionario";
    var _listDiccionario;
    
    $(document).ready(function() 
    {
    	//_spBodyOnLoadFunctionNames.push("Initialize()");
    	ExecuteOrDelayUntilScriptLoaded(initialize, "sp.js");  
    	//getList();
    	//addToolTipToList("body","0000FF",_listDiccionario);
    });
    
    function initialize(){
    	getList();
    }
    
    function addToolTipToList(where, color, list){
    	for( i=0 ; i < list.length ; i++){
    		addTooltipToText("body", "0000FF", list[i][0], list[i][1]);
    	}
    }
    
    function addTooltipToText(where, color, text, tooltipMessage) {
       $(where).replaceEachOne(text, '<label style="color:#'+ color + ';" title="' + tooltipMessage + '">$1</label>');
    }
    
    //Ejemplo en http://sharepointbloggin.com/2010/02/10/walkthrough-4-accessing-list-data-using-the-javascript-client-om/
    	function getList(){
    		//_listDiccionario = Array(new Array("elemento","Este es el mensaje"), new Array("mensaje","cosas rarascosas ")); //Para probar
    		
    		var ctx = new SP.ClientContext.get_current();
    		this.web = ctx.get_web();
    		ctx.load(this.web);
    
    		/*var webUrl = "http://c-jfmunoz:5000";  
    		var context = new ClientContext(webUrl); */
    		
    		// Get references to the lists we will use
    		var listObject = web.get_lists().getByTitle(_listName);
    		
    		ctx.load(listObject);
    		
    		// Get the list items for the list 
    		_listDiccionario = listObject.getItems();
    		
    		// context.load tells the object model to load the objects scalar 
    			// properties. Otherwise they will not be accessible 
    			ctx.load(_listDiccionario);
    			
    			ctx.executeQueryAsync(Function.createDelegate(this, this.onListsLoaded),
    									Function.createDelegate(this, this.onListsFailed));
    		}
    
    	/* 
    		Event handler called loading the contacts and companies lists
    		This method dynamically renders an HTML table to display the list data 
    	*/
    	function onListsLoaded(sender, arg) {
    		addToolTipToList("body","0000FF",_listDiccionario);
    		return false;
    	}
    	
    	function onListsFailed(sender, args) {
    		alert('failed to update title. Error:'+args.get_message());
    		return false;
    	}

UPDATE:

I change the name of the list from "Lista Diccionario" to "Diccionario" and now it works!!!