This document assumes that you have already set up Ogre on your system, and you are able to build the Ogre Tutorial framework using eclipse and MinGW. The libraries in these instructions are cegui-0.8 built with MinGW.
If you still need to install Ogre on Windows (with MingGW) see my instructions for installing Ogre and setting up eclipse.
Begin with a working Ogre project. I suggest copying and pasting the project in the eclipse project sidebar.
Right click on the project and select "Properties"
Click the "Advanced Settings..."
Click the "C/C++ Build" drop-down on the left.
Click Environment
At the top of the "Tool Settings" tab, select "[All Configurations]" in "Configuration:". You may need to scroll up, to see it.
Add an environment variable with the "Add..." button.
NAME=CEGUI_HOME VALUE=C:\GameDev\cegui
Edit the PATH environment variable so it now contains
NAME=PATH VALUE=C:\MinGW\bin;C:\GameDev\OgreSDK\bin;C:\GameDev\cegui
Click "Settings" under "C/C++ Build" on the left side of the window.
In the "Tool Settings" tab, click "Includes" under "GCC C++ Compiler"
Click the Add button icon (a document with a green plus sign on the right).
You will need to add the directories where the include files are for cegui. You can type exactly what appears below. Eclipse will use the variable ${CEGUI_HOME} here.
${CEGUI_HOME}\include\cegui-0
Click "Libraries" under "GCC C++ Linker". In the section "Libraries (-l)" add the following names:
CEGUIBase-0 CEGUIOgreRenderer-0
Add the library paths in the "Library search path (-L)" area.
${CEGUI_HOME}\bin
Click "Ok".
Ogre's Basic Tutorial 7 introduces Ogre with CEGUI. Make sure you follow the instructions specific to "CEGUI 0.8.x".