Selection problem

Hi all.
I’m little new with OpenGl and I’m using Visual C 6. I’d like to make a box with the mouse (clicking and moving it) in order to select the part of my ogl object (or one of the ogl objects) that is inside the box itself. After the selection I’d like to crop the selected part of the object. I think I’ve to use GL_SELECT but I can’t understand in which way.
Any idea or piece of code please?
Thanks in advance

download glut under the examples directory theres an example of using the selection buffer also check out the red book

You can also check chapter 14 of the OpenGL SuperBible book.