code: public static Date translateTime (final Date date, final TimeZone aSrcTZ, final TimeZone aDestTZ)
    {
      final Date newDate = new Date ();
      final int offset = aDestTZ.getOffset (date.getTime ()) - aSrcTZ.getOffset (date.getTime ());
      newDate.setTime (date.getTime () - offset);
      return newDate;
    }
docs: Translate a date &amp; time from a users time zone to the another (probably
  server) time zone to assist in creating a simple trigger with the right
  date &amp; time.
  
  @param date
  the date to translate
  @param aSrcTZ
  the original time-zone
  @param aDestTZ
  the destination time-zone
  @return the translated date