How to use glutBitmapCharactor in 3D space

Hello.

I want to display some text in OpenGL window(X window system). How can I use glutBitmapCharacter in 3D space?I don’t know its timing.

Should I use gluOrtho2D?I don’t know how to use this function and retain 3D matrix and 2D matrix steady.

I want to receive any advice.

sorry, my broken English.
thanks.

http://nehe.gamedev.net/lesson.asp?index=03

thank you very much.