I'm sure this has been thought of before but it occured to me that if you are only interested in viewing a Word document you can use Abiword or Open Office to convert the document to a html format and then view it with a browser. I suggest using Opera. When I tried it I found the user experience was great because Opera enlarges text smoothly with very nice wrapping. For the documents I tested neither Abiword or Open Office were perfect (some equations and symbols were messed up) but for general text documents it is more than sufficient. Also, while converting documents with Abiword is much faster than Open Office, Open Office did a little better with some symbols.

EDIT: If you save a Word document as a html file when using Word, and then look at it with Opera on the n900 (you have to copy the html file and corresponding folder with figures, gif files and so forth on the n900) the text, including equations comes out very nice. Similar result for the case of writing a document using Open Office and saving as html. Not quite as good with Abiword. (For example, it omitted the horizontal bar in a fraction)