Matt Broadstock has created a GUI to work with maintenance mode
This is a graphical utility to put Computers or Computer groups into Maintenance Mode for MOM.
It can be run from any system. It will query MOM for either Computer Groups or Computers that MOM manages and let you choose one or multiples of either. You can also manually type in a specific computer name (so you don’t have to browse through a large list)
You can download it here