Simple way to include Letterhead in Word Documents

[Kraniac]

I'm trying to create a sort of a template in M Word that has my letterhead in place plus document formatting for estimates, invoices, letters etc...with decimal tabs and proper margins for the word processing space of the document.

Most of my letterhead falls outside the actual word processing margins...above the top margin and to the left of the Left margin.

What's the easiest way to accomplish this?