Anther - First Map

[Drowned Fairy]

Hey, hey, hey guys,

After countless hours of writing my fantasy novel and going full Roman in Civilization (tm), I asked myself: "Why not make a map?"
And here I am.
Though I did not expect this type of map (full colored, detailed, etc.), I was completely happy with myself after knowing that it is apparently very easy to make continents (hooray!)

Anyway, after repeatedly reading and finding new tutorials and tips, I just want to say two things:
1. My mind is blown in awesomeness at the amount of details people put in their map and their tutorials.
2. My mind is blown in aggravation at some of the things that I barely understand.

If you guys don't mind, can anyone who knows relieve me of my problems by answering these questions?
I'll just leave out the details of how I gained them if you guys don't mind. Of course, I also don't mind if you guys want to know.
I. How do you use kilometers/meters/miles per pixel in your map?
II. What is the mathematical equation to determine how many km/m/miles per pixel does this particular resolution allow? (e.g 21,600 x 10,800 = 2 km/pixel. How do you know that?)
III. On some maps, like Forgotten Realms recent Faerun map, there's a bordered line in two colors showing numbers and miles, what is that (including the name so I won't forget) and how do you use it?

Here's the one from Faerun:


IV. And last but not least, how do you make the map, where instead of being colored, make it plain instead? (Like how you would find black, gray and white colored maps instead of the colored one in books)
Is it possible even after using the Threshold and Render>Cloud filter?

So without further ado, behold, my first map, made in Photoshop CS5.



Comments and Criticism would be greatly appreciated.
I would also like to thank Tear for the detailed and easy to follow tutorial from which this particular map is based of.

Cheers,

p.s Are there any websites you guys might know where I can get resources? (Textures, Patterns, Brushes, Fonts and the like)