Using nm-applet in KDE4
From ArchWiki
As of now knetworkmanager is not available for KDE4, and those of us using NetworkManager are going to have to settle with gnome's version of the network manager applet: nm-applet
First of you need to install networkmanager, read more on that here.
Once it's installed you need to set it up to run as a daemon, i.e. add it to /etc/rc.conf, and remove network:
DAEMONS=(syslog-ng networkmanager netfs crond alsa hal fam kdm)
Furthermore you have to exclude the interfaces you intend to use with networkmanager (also in /etc/rc.conf e.g.:
INTERFACES=(!eth0 !wlan0)
When that's done you need to install gnome-network-manager
# pacman -S gnome-network-manager
Then add yourself to the network group:
# usermod -g network your_username
And that should do it, you can now run nm-applet as a normal user, and switch between wireless and wired network without modifying rc.conf every time.