Because the file formats for the Microsoft Office products change often, and Microsoft does not publish the file specifications, the file formats have to be reverse-engineered by others who wish to read those formats. StarOffice and other Linux office programs have done so for at least Word6.1/'95 format, with some support for Word '97.
Applixware has released their latest version of their office suite, version 4.4.1, with full Office '97 support, both importing and exporting.
There is a program that converts Word '97 files to HTML, which is incomplete but improving. Unfortunately, as long as Microsoft fails to learn how to make backward-compatible changes to file formats (see HTML for an example of how to do it right), competitors will always have to play catch-up in this area.