Where to view MT4 account Leverage

Login your MT4, under Navigator Windows (Press Ctrl+N or go to 'view > Navigator'), mouse-over your account number. A yellow box will pop-out displaying your leverage (e.g. 1:500)

Alternate method:

Open the MetaQuotes Language Editor from the MT4 tools menu and create a new script like this:

//+------------------------------------------------------------------+
//|                                                     leverage.mq4 |
//|                      Copyright © 2012, MetaQuotes Software Corp. |
//|                                        http://www.metaquotes.net |
//+------------------------------------------------------------------+
#property copyright "Copyright © 2012, MetaQuotes Software Corp."
#property link      "http://www.metaquotes.net"

//+------------------------------------------------------------------+
//| script program start function                                    |
//+------------------------------------------------------------------+
int start()
  {
//----
Print("Account #",AccountNumber(), " leverage is ", AccountLeverage());  
//----
   return(0);
  }
//+------------------------------------------------------------------+

Compile the script and execute it and the leverage is shown in the Experts tab.