if it's a newer laptop you would have to remove the drive, then use a sata to usb adapter to hook it up to your netbook.
Removing the drive can be a either easy or a gaint pain depending on each laptop.
(edit: adding extra info)
What the above poster said would work for installing or transfering stuff from disk to your netbook. You would have to share the DVD drive on the laptop and then set a network drive on the netbook. However you couldn't do this to say reinstall the OS on the netbook.