In summary Network Manager is a connection manager and right now supports working with Ethernet/PPP/Wireless.
Network Manager attempts to make networking invisible. When moving into areas you've been before, Network Manager automatically connects to the last network the user chose to connect to. Likewise, when back at the desk, Network Manager will switch to the faster, more reliable wired network connection.
It is recommended distributions use Network Manager 0.7 from subversion.
In order to associate to a wireless network and scan NM uses wpa_supplicant as its back-end.
Debugging Network Manager
If you have issues with Network Manager we recommend you start Network Manager with debugging options.
Hacking on NM
In order to build NetworkManager you need the GNOME gnome-autogen.sh script, found in the 'gnome-common' SVN module. Grab that and install it, if you don't have it already:
svn co svn://svn.gnome.org/svn/gnome-common/trunk gnome-common cd gnome-common ./autogen.sh --prefix=/usr cd macros2 make sudo make install
Next, grab NetworkManager from SVN HEAD. To checkout and build from SVN HEAD:
svn co svn://svn.gnome.org/svn/NetworkManager/trunk NetworkManager cd NetworkManager ./autogen.sh --prefix=/usr --sysconfdir=/etc --localstatedir=/var make sudo make install
And if you want to play with the applet, you need network-manager-applet, too:
svn co svn://svn.gnome.org/svn/network-manager-applet/trunk network-manager-applet cd NetworkManager ./autogen.sh --prefix=/usr --sysconfdir=/etc --localstatedir=/var make sudo make install