For us KDE users, when we go to Gnome, there is nothing to compare with KDE's File Manager - Super User Mode. Well, that is not exactly true. You can create a Nautilus SU icon that works just the same way.

RightClick Desktop
Click Create Launcher
Type: Application
Name: Nautilus SU
Command: gnomesu nautilus
Click OK

Once the icon is on the desktop, you will want to change the icon.
RightClick Nautilus SU icon
Click Properties
Click the springpad icon
Browse to /usr/share/icons/hicolor/scalable/apps/
Select Nautilus.svg
Click Open and it will take you back to the properties
Click Close

Test your icon
It should ask for the root password when you open Nautilus and you should have root access to the file system.
You can now copy the icon and place it anywhere you want it.