I just place it in the case so that it won't short out. Gaffer's tape would be one idea but tape tends to generate far too high a static charge when you peel it off the roll so I'd stick with cardboard or placing it in a smart and safe place so I could clone the old drive to the new drive. The drive maker supplies the clone software.
If I just want to copy the data files out I could opt for a nice USB 2.0 drive housing.
Bob
I just bought a new hard drive and I'm wondering what the best way to get all of the data from my old HD onto the new one is. I was thinking of installing it as a second hard drive and moving all of my files to the new one (keeping windows on the old one) but my computer only has one hard drive bay. Could I fix it in place with gaffer tape or something or will I have to stick with one HD?
If so, is there a way to copy everything from the old HD to the new one or will I have to reinstall everything?

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic