I have heard it said that you should remove the power amp tubes when shipping, is this true? Any advice about carriers (UPS vs Fedex)? Any special tricks for packing?
Yes, you'll definitely want to remove the power tubes and wrap them seperately. As for carrier, it doesn't matter too much. People have had good and bad luck with all of them. Just make sure you pack it well and everything should be alright.
A good tip for boxes is to check in the phone book for providers of Cisco network equipment. Some of their larger enterprise-level switches come in great sturdy boxes and some even have mini pallets in them.
Double box. If possible, find a very tight fitting box, and another box with room for 3-4 inches on every side. Bubble wrap is great, crumpled newspaper works ok. If you can find a piece of styrofoam to wedge between the speaker magnet and the bottom of the amp to support the speaker, even better. Baffle boards don't always survive a good drop.