In Word 2003 one can save as WEB PAGE and get document translatted into HTML coding. You can use VIEW and see SOURCE CODE to get the HTML coding for that file.
In Word 2007 you can save as web page but I can't find how you VIEW the source code that was created with it.
What you need to do is right-click on the file and select Open With... and use notepad to view the HTML.
Shield your eyes; it's ugly, ugly code.
EDIT: To alleviate some of the bloat and make things more legible, I suggest http://textism.com/wordcleaner/ - I've had pretty good results with it in the past, but it only works for files up to 20kb.
For SO bonus points, check out Jeff's C# code here: Cleaning Word's Nasty HTML.
You can also change the extension of the .docx to zip, then view the contents. A .docx file is actually a zip file with several .xml files inside... but that probably won't give you what you're looking for.
If you've only got a simple HTML page (I can't imagine it being much more than that if it was wrote in Word) you can just view the source in your browser.