After installing Ubuntu 9.10 on my laptop shortly after its release, I moved from the default network manager to Wicd. This was primarily due to the fact that nm is unable to select between two cards installed at the same time, and throws a horrific hissy fit. Wicd has this capability.
In any case, upon login Wicd would ask for the root password in order to access network cards, which is incredibly irritating for a program that is meant to intialise as a daemon during bootup and typically be connected to the network by the time a user has actually logged in. A fix was needed!
After much googling a solution to the issue presented itself here. The problem occurs when the daemon is not properly started during bootup. When the Wicd tray icon subsequently starts it then fails to connect to an existing daemon and attempts to initialise the daemon itself, requiring the password input.
The fix involves adding the line exec wicd to the bottom of /etc/init/networking.conf.
So, in the terminal:
sudo gedit /etc/init/networking.conf
Copy paste "exec wicd" (without quotes) to a new line at the bottom of the file
Save and quit
Reboot the computer
Hopefully that will have sorted it!