I've received about 12 bikes from ebay sellers. The best packed bike had pipe insulation neatly taped around all the tubes. This was a complete surprise as this particular seller was actually proud of his "Vintage Mobile Home!".
The worse packed bike was from a guy that said not to worry, he was having it professionally packed. It was disassembled further than necessary and all the little bits were thrown in a sandwich bag that was taped open to the side of the box! All the parts fell out of the bag and most escaped out the poorly taped up corners. I think his "Pro" packer was one of his kids.
The fact that a bike shop packs and ships it may or may not be a good thing. Some do a fine job, others get lazy or don't care if your paint gets scratched.
In spite of all the above, I've had good overall experiences. Take a look at the sellers past feedback. If they've never shipped a bike you might offer a link to a website on how to do it. Here's a good one...
http://chainwheeldrive.com/page.cfm?PageID=286