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;
    }