Colors/Textures

This is a noob question but… I’ve been using blender for a while and to make it so stuff was different colors I alwaysed used different objects, but I have seen different colors and textures in one object by somehow doing it with the mesh. I have tryed adding more materials and assigning it to a spot but that didn’t work, so how do you do it?

http://www.blender.org/modules/documentation/htmlI/x4448.html

Do you mean like that?

-Laurifer