One of the PIE options is to make html files, sure. But you can also make a .lit book that has the DRM removed - it works exactly like any other .lit file but it is no longer tied to your activated device(s).
You can also use uBook (www.gowerpoint.com). I personally prefer it to Microsoft Reader. It will read (and remember your page etc) for txt, html, rtf, pdb and prc files.[/url]