My opinion:
Step 1) pick a day where NO ONE will be bothered by it being down (this of course is a challenge in it's self)
Step 2) Notify local carrier of T1s and/or service of a temporary outage
Step 3) Complete a FULL back up of all information on system (never want to shut it down with out this...it may not come back, remember)
Step 4) Back up any VM system if need be
Step 5) Courtsy shut down Meridian Mail (if applicable)
Step 6) Disable DCH and Loops (not real nessisary, but a good practice)
Step 7) Make sure there are no users still connected and you've got a sufficiant service on a moible phone or an analog set (in case something goes wrong and you need to call out)
Step

Toggle that sucker off line (Primary cabinet, large toggle for power)
Step 9) Pray Pray Pray (if your into that) that all will come back up successfully....if not, start calling for help...if so (and this works if it doesn't also) go to the nearest pub and drink heavily!
