A few hours before "the event" water the roses with a deep soaking to loosen and soften their dirt up. Try and do the transplanting early in the morning or in the early evening, not during hot, mid-day hours. Absolutely NO fertilizing for the first 4 to 6 weeks. Let the roses get used to their new home soil before they take on any new supplements.

When the roses have been transplanted water them every day for the first 10 days then you should be able to slowly backtrack to your normal watering cycle. That's all I can think of for now, but I'm sure some of the experts can weigh in and add some more :)

I think Blue gave you good advice. Make sure you get as much root ball as possible and try to disturb that ball as little as possible. Have all of your new holes dug and ready before you start to dig them out. If you have to move them over a distance you can put the root ball on a tarp and drag it to the new spot or in a wheel barrow (although they're heavy and hard to lift that high sometimes) so you're not handling the root ball a lot. You may want to cut them down some before you move them too. A reduced sized root ball can sometimes have problems trying to support all the top growth. You may see some wilt in the beginning but that should go away fairly quickly. If not check them right away to make sure there aren't any air pockets under ground. I lost a rose once because of that.

Will spraying them, post-move, with one of those anti-wilt sprays help? Or will that stress them further?

I just move them, give them shade for a couple days if it's sunny and make sure they have plenty of water.

While many say it's not necessary, I find cutting back prior to the move pretty well guarantees survival with much less stress that trying to salvage much top growth.
I say bite the bullet. You may miss a bloom cycle but you would anyway after having to remove dead buds and blooms caused by stress. Water well and often after the move and don't fertilize until it shows signs of good growth.

The only thing I would add to everyone else's excellent advice is to make sure that the receiving location is as welcoming as possible. If you're going to amend the soil there -- and there has been a great deal of back and forth here about the wisdom of doing that -- get that out of the way before the day you move the roses. Give it some extra moisture for a few days before Moving Day as well. Oh, and pray for cooler weather for the first couple of weeks after the deed is done.

Kay

tomtuxman: Just found this tutorial on YouTube that might be helpful -
"Moving A Rose During The Growing Season"

Yes, Paul Z's clever idea about the two parallel shovels (video) really works.

If you don't manage to move a solid rootball, I recommend just defoliating the rose. Then it can't die of water stress and it will quickly leaf out. I't like planting a bare-root. Cutting back is also effective, but there is some food energy stored in the canes that you would be losing.