diff --git a/src/Makefile b/src/Makefile
index 243049d..0c51c1e 100755
--- a/src/Makefile
+++ b/src/Makefile
@@ -81,7 +81,7 @@ chrome_sources := $(chrome_sources_js) \
 modules_dir := modules
 
 # The sources for the module files.
-modules_sources := $(wildcard $(modules_dir)/*.js)
+modules_sources := $(wildcard $(modules_dir)/*.js) $(wildcard $(modules_dir)/*.jsm)
 
 # The sources for the XPI file. Uses variables defined in the included
 # Makefiles.
diff --git a/src/chrome/content/overlay.js b/src/chrome/content/overlay.js
index 9055004..34b19af 100644
--- a/src/chrome/content/overlay.js
+++ b/src/chrome/content/overlay.js
@@ -1,10 +1,9 @@
 /* -*- Mode: js2; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 
-// TODO: Components.utils.import("resource://gre/modules/Services.jsm");
+Components.utils.import("resource://gre/modules/Services.jsm");
 Components.utils.import("resource://gre/modules/ctypes.jsm");
-Components.utils.import("resource://moztray/LibC.js");
-Components.utils.import("resource://moztray/LibGObject.js");
-Components.utils.import("resource://moztray/LibGtkStatusIcon.js");
+Components.utils.import("resource://moztray/LibGObject.jsm");
+Components.utils.import("resource://moztray/LibGtkStatusIcon.jsm");
 Components.utils.import("resource://moztray/commons.js");
 
 const MOZT_ICON_DIR = "chrome/skin/";
@@ -41,7 +40,7 @@ mozt.Handler = {
   _getAllWindows: function() {
     mozt.Debug.debug("_getAllWindows");
     var baseWindows = new Array();
-    var e = mozt.Utils.windowMediator.getEnumerator(null);
+    var e = Services.wm.getEnumerator(null);
     while (e.hasMoreElements()) {
       var w = e.getNext();
       baseWindows[baseWindows.length] = this._getBaseWindow(w);
@@ -132,7 +131,7 @@ mozt.Main = {
       // instanciate tray icon
       LibGtkStatusIcon.init();
       this.tray_icon  = LibGtkStatusIcon.gtk_status_icon_new();
-      var mozApp = mozt.Utils.appInfoService.name.toLowerCase();
+      var mozApp = Services.appinfo.name.toLowerCase();
       var iconFilename = MOZT_ICON_DIR + mozApp + MOZT_ICON_SUFFIX;
       LibGtkStatusIcon.gtk_status_icon_set_from_file(this.tray_icon,
                                                      iconFilename);
@@ -153,7 +152,7 @@ mozt.Main = {
                                   mozt_activateCb, null);
 
     } catch (x) {
-      Components.utils.reportError(ex);
+      Components.utils.reportError(x);
       return false;
     }
 
@@ -220,3 +219,4 @@ mozt.Main = {
 // https://developer.mozilla.org/en/XUL_School/JavaScript_Object_Management.html
 window.addEventListener("load", function (e) { mozt.Main.onLoad(); }, false);
 window.addEventListener("unload", function(e) { mozt.Main.onQuit(); }, false);
+// TODO: put all mozt into a module (jsm) so it's loaded only once
diff --git a/src/modules/LibC.js b/src/modules/LibC.jsm
similarity index 100%
rename from src/modules/LibC.js
rename to src/modules/LibC.jsm
diff --git a/src/modules/LibGObject.js b/src/modules/LibGObject.jsm
similarity index 100%
rename from src/modules/LibGObject.js
rename to src/modules/LibGObject.jsm
diff --git a/src/modules/LibGdkWindow.js b/src/modules/LibGdkWindow.jsm
similarity index 99%
rename from src/modules/LibGdkWindow.js
rename to src/modules/LibGdkWindow.jsm
index 900a234..6bbb6fa 100644
--- a/src/modules/LibGdkWindow.js
+++ b/src/modules/LibGdkWindow.jsm
@@ -46,7 +46,7 @@ const Ci = Components.interfaces;
 
 Cu.import("resource://gre/modules/ctypes.jsm");
 Cu.import("resource://gre/modules/XPCOMUtils.jsm");
-Cu.import("resource://moztray/LibGObject.js");
+Cu.import("resource://moztray/LibGObject.jsm");
 
 XPCOMUtils.defineLazyGetter(this, "libgdkwindow", function() {
   var libgdkwindow = ctypes.open(LIB_GDKWINDOW);
diff --git a/src/modules/LibGtkStatusIcon.js b/src/modules/LibGtkStatusIcon.jsm
similarity index 96%
rename from src/modules/LibGtkStatusIcon.js
rename to src/modules/LibGtkStatusIcon.jsm
index d6cbc03..7c83b67 100644
--- a/src/modules/LibGtkStatusIcon.js
+++ b/src/modules/LibGtkStatusIcon.jsm
@@ -20,8 +20,8 @@ var LibGtkStatusIcon = {
       throw ("Could not load JS-Ctypes");
     }
 
-    Cu.import("resource://moztray/LibGObject.js");
-    Cu.import("resource://moztray/LibGdkWindow.js");
+    Cu.import("resource://moztray/LibGObject.jsm");
+    Cu.import("resource://moztray/LibGdkWindow.jsm");
 
     try {
       // Try to start up dependencies - if they fail, they'll throw
diff --git a/src/modules/commons.js b/src/modules/commons.js
index 80fc524..68c5412 100644
--- a/src/modules/commons.js
+++ b/src/modules/commons.js
@@ -12,7 +12,8 @@ const Cc = Components.classes;
 const Ci = Components.interfaces;
 const Cu = Components.utils;
 
-Cu.import("resource://moztray/LibC.js");
+Cu.import("resource://gre/modules/Services.jsm");
+Cu.import("resource://moztray/LibC.jsm");
 
 const FIREFOX_ID = "{ec8030f7-c20a-464f-9b0e-13a3a9e97384}";
 const THUNDERBIRD_ID = "{3550f703-e582-4d05-9a08-453d09bdfdc6}";
@@ -77,12 +78,7 @@ mozt.Debug.init();
 
 
 mozt.Utils = {
-  prefService: Cc["@mozilla.org/preferences-service;1"].getService(Ci.nsIPrefService)
-    .getBranch("extensions.moztray."),
-
-  appInfoService: Cc["@mozilla.org/xre/app-info;1"].getService(Ci.nsIXULAppInfo), // appInfoService.name.toLower
-
-  windowMediator: Cc["@mozilla.org/appshell/window-mediator;1"].getService(Ci.nsIWindowMediator)
+  prefService: Services.prefs.getBranch("extensions.moztray.")
 };