There is a huge difference in how even "professionals" pack bikes. I have received them wonderfully and terribly packed.
the worse two ever were from "professionals". I would disagree with the revered List meister somewhat (for the first time ever). If you know for sure how they do the job, by all means have them do it. If you don't it is such a crap shoot that you should do it your self. Here's how.
Get some of those plastic spacers that go between the dropouts from your LBS. Tape them carefully into place. get some air pack and some pipe wrap. Wrap all tubes including the forks, stays, etc with it. The bars should be taken loose and wrapped and separated from the frame by a bit of cardboard. This a great place to use a lot of bubblewrap. Either pad the rear derailleur heavily or take it loose and bubble wrap it. The seat post comes out and is bubble wrapped. I don't think you need to remove the seat from it. Everything is wrapped and padded. A small box goes inside for the skewers, etc. Again, all this is padded too. You can take some plastic ties through the bike box (I didn't mention it, buy your LBS will give you one) around the frame to keep it from moving. I like to ship wheels in a separate box, but if you need to use one box, separate the bubble wrapped wheels from the frame with a couple layers of cardboard. Remember all things in the box are wrapped and padded. No possible metal to metal contact is permissible. When you take it to UPS, insure it and realize that it will be shipped flat. "This side up" does not mean squat to these folks nor should you expect it to. The box is way over taped, not just the openings, but all possible future openings.
If this all seems like a lot of work to you, you're right. Like Dale says have a good pro do it for you. If you really don't know of any then do it your self. It is not rocket science, but it needs to be over done.
Sorry to take up the space on your E-Mails of those who know how to do this, but the variance of how bikes are shipped is so huge, that you can't count on anyone else unless you know how they do it.
Tom Sanders
Lansing, Mi