Does the mac mini have a cd/dvd drive in it?

True, though you can usually use the System Profiler or System Information application to determine if the interface of the Mac has a drive connected to it, unless it is not getting power from it at the time or elsewhere.

The 2011 Mac Mini doesn't have a CD/DVD-drive inside.

You can buy this external one http://store.apple.com/us/product/MC684ZM/A?fnode=MTY1NDA0Nw

Stefan

And if that's too expensive, any of the ones on http://www.macsales.com/ should work.

Or, you can buy a used 2010 mini as they did have an internal one.

Do you need to have a disk in it for it to work?

The optical drive in/connected to a Mac will not show in Finder unless there is a disk in the drive.