I was interested in this official Microsoft Word blog post on using WordPad to find out your printer’s printable area: http://blogs.office.com/b/microsoft-word/archive/2010/09/03/print-borders-without-problems.aspx.
However, the information provided in this post didn’t work for me in WordPad on my Windows XP computer, nor on my Vista laptop.
Instead, I tried something similar in the various versions of Word that I have and I was able to see the minimum margins that my printer requires.