Quote: "1) What is light mapping (as far as DarkBasic Pro is concerned)"
Lightmapping is a very efficient way of putting lights and shadows into a game, because all of the lighting is pre-rendered onto textures. These textures are then loaded, and use some sort of blend mapping to be drawn onto the object. You should understand that "lightmapping" is nothing more than that: just prerendered lightmap textures blended onto the object.
Quote: "2) Can "Set Light Mapping On" be used to make textures illuminate with lack of light?"
I'm not sure about how the native dbpro command works, but if used properly, lightmapping would allow you to have static lighting on an object without needing any "dynamic" lights. Most people use
set light mapping on in conjunction with
set object light, so that the object has only the lightmap.
Quote: "3) Will I have to learn about shaders to acheive "light mapping"? (If so I will hold off on this part of my learning till I am ready to tackle those.)"
Simple answer: probably not!

If you want to apply lightmapping through code, dbpro has a native lightmapping command, and if that doesn't work, there are shader alternatives that people have written, that are relatively easy to use without any shader knowledge.
Also, some model or level editors (3DWorldStudio for example) actually save the model file already with the object multitexturing applied. If you can figure out how to do this, it'll save a lot of time, because you do not need to add any code to load and apply a lightmap. I also believe that Dark Lights does this.