NetworkManager consists of two parts: one is on the system level daemon that
manages the connections and gathers information about new networks. The other 
is a systray applet that users can use to interact with the NetworkManager 
daemon. 

Security
~~~~~~~~
To allow users to connect to the NetworkManager daemon they have to be in the
group "netdev". If you want to add a user to group "netdev" use the command
"adduser username netdev" or one of the graphical user management frontends.
After that you have to reload dbus with the command "/etc/init.d/dbus reload".

Configuration
~~~~~~~~~~~~~
Only devices that are *not* listed in /etc/network/interfaces or which have 
been configured "auto" and "dhcp" (with no other options) are managed by NM.

This way you can setup a custom (static) configuration for a device and NM 
will not try to override this setting.

Examples:

1.)
auto wlan0
iface wlan0 inet dhcp
-> This device is managed by NM.

2.)
auto wlan0
iface wlan0 inet dhcp
	wpa-conf /etc/wpa_supplicant/wpa_supplicant.conf
-> This devices is *not* managed by NM because it has additional options.

3.)
iface wlan0 inet dhcp
-> This device is *not* managed by NM because it is not set to "auto".

4.)
iface eth0 inet static
address 192.168.1.10
netmask 255.255.255.0
gateway 192.168.1.1
-> This device is *not* managed by NM because it is configured as "static" and
   has additional options.

5.)
Device is not listed in /etc/network/interfaces.
-> Device is managed by NM.