Beginning Texturing

I am a complete noob when it comes to this, so I was wondering if anyone has any really good tutorials for applying color and image textures in Blender? I need multiple colors on a single plane, but whenever i select the areas of a subdivide I want changed and select a new color, the entire plane changes, not just the selected squares. Any help would be greatly appreciated, thank you.

Unless you have figured it out already, the answer lay in the Edit Mode, Edit Tab Buttons. I think this screenshot does a good job describing it :yes: