There are a lot of wireless manager software available for Linux, some of the most common ones are:
NetworkManager, which is the default for Ubuntu KwifiManager, which is the KDE’s default one
I used to use wifi-radar, but now I am using wicd.
Use your package manager to install it on your Linux distribution.
Debian / Ubuntu
sudo aptitude install wicd
sudo pacman -S wicd
sudo emerge wicd
Read How to install wicd for more installation methods.
Once installed, you need to make the daemon to start at each boot of your Linux, this will be automatically configure for most distros, but for Arch you will have to make it yourself, so:
Starting wicd as daemon on Arch Linux
You will have to edit /etc/rc.d file and add wicd to the DAEMONS line, it may look like this:
DAEMONS=(syslog-ng network netfs crond alsa hal !wifi-radar !fam wicd cpufreqd sensors)
Once the daemon is running, you can start the client, which is done with.
It will appear on you Desktop panel, if you are using OpenBox and you are not running any panel, you will have to start it with:
If you go to advanced configurations, you will have the option to configure static IPs or DNS servers.
You can also use it to, configure you wired networks, in the same way, once the cable is connected you will see the option for wired networks available, like this screenshot shows.