zion.solutions - 2013-01-02

The setting is within config.inc.php in this block.

 * Email settings

// ------------
// The following settings determine who should be emailed when a booking is made,
// edited or deleted (though the latter two events depend on the "When" settings below).
// Set to TRUE or FALSE as required
// (Note:  the email addresses for the room and area administrators are set from the
// edit_area_room.php page in MRBS)
$mail_settings['admin_on_bookings']      = FALSE;  // the addresses defined by $mail_settings['recipients'] below
$mail_settings['area_admin_on_bookings'] = FALSE;  // the area administrator
$mail_settings['room_admin_on_bookings'] = FALSE;  // the room administrator
$mail_settings['booker']                 = TRUE;  // the person making the booking
$mail_settings['book_admin_on_approval'] = FALSE;  // the booking administrator when booking approval is enabled (which is the MRBS admin, but this setting allows MRBS                                to be extended to have separate booking approvers)   

You will also need to setup a from address in the same file a bit further down under Email miscellaneous.
Hope this answers your query.