When Remote Disc does not appear on Mac OS X
I've used the remote disc feature of OS X a few times. It's pretty easy: you enable CD and DVD sharing on one Mac, and put the DVD in it. Then on the other Mac, you click on Remote Disc in the Finder sidebar, and you can attach the remote disc.
This is exactly what the online help from Apple says, and it works great, except when it doesn't.
Sometimes, the Remote Disc item just isn't there in the sidebar. And there's no way to make it appear, in finder preferences or system preferences.
For example, I was able to do this from my Mac Mini; Remote Disc was there. But on my iMac, and most critically on the Macbook I was trying to set up that had a broken DVD drive, it was not there.
Here is the command line magic you need:
defaults write com.apple.NetworkBrowser EnableODiskBrowsing -bool true
defaults write com.apple.NetworkBrowser ODSSupported -bool true
Then you need to log out and log back in again (or maybe just kill Finder?).