Here's the 20 steps (actually 21) I use to ship a DMD-type pinball terminal to terminal in Canada (I use Maritime-Ontario or Sameday). I learned this from Tanman, and borrowed some text from an e-how, but since I was sending it to someone shipping me a pinball, I thought I'd pass it on in case it helps anyone else (or someone wants to add to it):
Take some pictures of the game before and after you wrap it; this can serve as proof of pre-shipment condition. Obtain a quotation and pre-shipment number from your shipper, that # should be added to the labelling. Also inquire about insurance. Although the shipment would normally be covered by home owner's insurance, it is a safety. Note however that the shipper may choose not to insure it beyond a nominal value. Assure them of how well it will be packaged. Try to keep it all to one package, less chance of a head getting lost!

Step 1
Remove the loose pinballs from the game cabinet and play field. You do not want these rolling around during shipment, causing untold damage to the game parts. With the playfield glassoff, they can be removed using a diagnostic function in the Test Menu, or you can usually find the solenoid (like a plunger rod in a coil under the playfield) that normally puts the balls into the shooter lane by hand (do so with the power OFF). Also remove the coin box, owner's manual and almost anything else that is loose inside the cabinet (no need to worry if you can’t get all the loose screws or old bulbs that may be there.) Set all of these items aside.
Step 2
If the machine has head bolts, carefully remove the backglass and speaker panel (leave wires attached as you will be putting this back) to get to the bolts, unscrew them (be sure the safety latch at the back is locked or have someone else hold up the head to keep it from falling forward). Put the bolts with other loose items. Attache the backglass keys back inside the cooin door, or keep them with the loose items.
Step 3
Remove the backbox latch (the hinged part), this often catches on things and can scratch the floor, so best to remove it (usually 4 hex head screws) and pack it with the other loose items.
Step 4
If the backbox backglass rattles, gently wedge a couple pieces of folded paper or light cardboard to help hold it tightly in place. IF you must use tape, use Scotch Magic Tape (the “invisible type” used to wrap presents) as this is easier to remove from glass later.
Step 5
Push the power cord up all the way inside the cabinet. If there is a coverplate preventing the cord from going inside you can unscrew this plate and then you should either be able to unplug the cord, or push it inside. Put the loose cord and plate/screws together with the loose items.
Step 6
Secure foam / bubble wrap / cardboard padding around the plunger that sticks out (another option is to remove the plunger before doing the wrapping). Secure foam padding / cardboard around any “topper” that sits on top of the machine’s head (or remove it if possible).
Step 7
Lock or tape the coin door so that it won't swing open. Be careful not to put much tape on the cabinet decal itself, just metal to metal. Tape the key into the coin slot (using packing tape which sticks better).
Step 8
Carefully fold down the backbox onto the cabinet. Place foam or cardboard padding underneath the backbox to protect the rails on either side.
Step 9
Wrap five or six tight layers of shrink wrap around the entire game except the legs, thereby locking the head down firmly. You can find shrink wrap at a moving supply store; buy it on a roll, normally 2 ft wide, or at least the wider stuff is best. You can also lock the head to the cabinet by using a tiedown as well, but the shipping wrap is fine if the other procedures are followed.
Step 10 (optional)
Add some Styrofoam padding to the back end of the machine, or you can skip this layer if using double thick cardboard. The purpose is to cushion the machine should it be accidentally put beside something sharp or touched by a fork list arm.
Step 11
Put the back end of the pinball machine up on a stool or have a friend hold it up as you loosen and take off the back legs. Then gently lower the back end of the pinball machine down to the ground. Check to make certain there are no nails or sharp things or broken gliders poking down, if you were to move it on a wooden floor with anything poking out on the back, it will scratch a floor. Lift on the front legs until the pinball is standing upright on it’s back end (there are gliders there for this purpose usually). Then you can remove the front legs.
Unscrew the leg lifters from the legs and add them along with the leg screws to the loose items pile. Removing these makes the legs shorter and easier to nest together.
Step 12
Place the bolts, leg lifters, coin box, pinballs, owner's manual and any other loose items from the pinball game into a box (or the coin box) stuff it with paper to keep things from rattling around too much and wrap it with some bubble wrap or cardboard.
Step 13
Nest and wrap the four legs several times in plastic wrap. Tape the leg bundle and the parts box to the pinball, in the right angle where the head meets the cabinet. The legs will sometimes stick out a little bit on either side, its a good idea to add some foam or cardboard to the parts that stick out. You want to make certain that if the legs shift or rattle, that they are padded well enough so that they won't damage the cabinet.
Step 14
(Optional) At this point you can put some foam padding or Styrofoam (1/2 insulation works well) to all edges of the game, and add a few more tight layers of shrink wrap over the entire game. Or you can skip this added layer IF using good quality double thick cardboard.
Step 15
Wrap another five or six tight layers of shrink wrap around the entire game, legs and parts box. Don't skimp on the wrap; keep layering it on until you think it is thick. Now you have a pinball mummy.
Step 16
Place a layer of oversize heavy cardboard on the floor and move the game on to it (this will be the back), add some cardboard or Styrofoam into the corners if possible to give some padding to the corners. Or make certain the cardboard is “double thick” is also fine. Fold up the sides, taping to the shrink wrap as necessary to hold it into place. Do the same now to the coindoor front side of the cabinet. Be aware when using a box cutter that it is very easy to slice through to the cabinet and undo all the fine work you have just done, do the cutting AWAY from the pinball cabinet.
Step 17
Finish by covering the machine sides all around in thick cardboard and taping securely.
Step 18
Take the shipping sheet with the From, Ship To, and Quote # clearly visible and tape 3 copies to the machines’ top and two sides. Mark which way is up (playfield glass) on the machine. (It can be palletted and shipped standing up on it’s back side, but is usually much safer (because of the lower centre of gravity), to ship it laying down on its bottom, sitting like a coffin. Some shipperse don't like this since it sticks over a standard pallet but you can speak to them about which way will be best.) Make certain the Top is clearly marked.
Step 19
Rewrap the outside of the cardboard box in 4 to 6 layers of plastic wrap, including the front and back (which you can tip the machine back on to its bottom to do). This helps in case it is raining during transport. The shipping sheets should still be (and must be) visible through the plastic. Assuming that the shipper will pallet the game for a LTL shipment, you are done packing.
Step 19a
I personally use shippers that will pallet the machine for you (since they sometimes wrap more than one item going to your destination terminal on the same pallet). If YOU must pallet the machine, this can be done beforehand or usually at the terminal. Get a pallet, and at least 4 large tie downs. Find out from the shipper if the machine must stand upright, or if it can lay down on its bottom. Strap the machine tightly to the pallet. Ask the shipper if they can re-shrink wrap the load to the pallet (they have a method for doing this where the pallet is spun and automatically wrapped often at no extra cost. Your mileage may vary.
Step 20
Take the machine to the shipping terminal. Don't forget your driver's license and credit card if not pre-paid. Bring a copy of the quotation number and ship to information (or copy of the Bill of Lading) to the shipping desk and then they will give you instructions on how to pay for the shipment and to back your vehicle into the loading bay and a shipper will usually help get the machine from you. Ask them nicely at this point to put it on a pallet and re-wrap it with shrink wrap if possible.
Have some ID and the Bill of Lading ready to be able to leave the terminal.