The thing that I know is NetworkManager has an applet that appears in the notification area of the panel - either Gnome or KDE - it monitors and controls network cards.
At least as far as Fedora 8 is concerned its primary use is in connection with wireless cards.
I've just been doing a bit of testing and it is linked with the NetworkManager service and does not appear if that is stopped. It's also identified, when you right click on its icon and select "About", as "NetworkManager Applet 0.7.0".
This quote from the fedrora 8 release notes:
Since knetworkmanager does not work with the version of NetworkManager available in this release, the KDE Live images use nm-applet from NetworkManager-gnome as a replacement. The gnome-keyring-daemon facility saves passwords for these encryption technologies. The knetworkmanager package in this release is a script that calls nm-applet. The knetworkmanager package will be updated to provide a KDE frontend when a compatible version is available.
gives a clue as to what the 'nm-applet' is.
I don't actually see it listed on a machine either with or without NetworkManager running though.
Give me some clue as to how you discovered it and how it appears when running.