Wicd is a wlan-gui written in python which helps setting up a wlan-connection.
First you need some packages installed to get wicd working:
apt-get install python-glade2 python-gtk2 wireless-tools wpasupplicant dhcp3-client
Now you can download the *_all.deb version of wicd stable from here and install it with:
dpkg -i *_all.deb
The wicd daemon should automatically be started after installation. You can start the wicd-client now with:
In Preferences you should give in: eth0 for wireless and usb0 for wired connection.
Wicd should show now your networks. Connecting to one of them is not working at the moment. You will always end up with "Putting down interface..." and nothing happens after that but work is in progress about this problem: click.