This is now a Mod
Control Panel > Site Mods > Get Site Mods > Look for "Vote Notification"

 var vote_notification_use_growl = true;
 var vote_notification_title = "New vote!";
 var vote_notification_icon = "/globalImages/CP/tick.png"; // check mark icon
 var vote_notification_time = 5000; // in milliseconds
 var vote_notification_width = 300; // in pixels

• Setting the growl variable to true will open a growl window with your new mail message.
  Click here to test it (you can change the default style of the growl window by adding the growl mod - check out this post on how to do that).
  Setting it to false will open a facebox window with the same message.
  
  var vote_notification_use_growl = true;


• The title of the popup window is set using the title variable. I've included an image in the title as an example:
  
  var vote_notification_title = "New vote!";


• The icon that is next to the title is set in the icon variable. The default is the same check mark used in the top menu
  
  var vote_notification_icon = "/globalImages/CP/tick.png"; // check mark icon
• The content of the popup window is now pulled directly from the tooltip of the vote notification. It contains the number of votes left to vote on.


• The time variable is used by the growl popup, it sets how long this window is displayed (in milliseconds) on screen before disappearing.
  
  var vote_notification_time = 5000;


• The width variable allows you to adjust the width of the growl window popup. By default it is 500 pixels wide
  
  var vote_notification_width = 300; // in pixels
• Note: The popup windows will continue to open on every page of your site until the user votes... so using the facebox option may be a bit annoying to your users.