Adobe Reader can be downloaded to any PC for free, and will convert your Word file to a PDF very easily. If you intend people to read those on any e-book reader, you should select the ISO-compliant setting, which will tag the PDF for reflow. Keep in mind, though, that many e-book readers don't support reflow, so your PDF may require them to scroll left to right, as well as down, to read your text... prepare to hear howls of discontent over that!
As for ePub: Word files are notoriously bad when it comes to converting from its native format to any strain of HTML (of which ePub is based). However, ePub creation programs like Sigil will allow you to copy and paste your book (chapter by chapter is usually best) into the document window, and it will do the rest. The additional steps you'll need to take (checking that your TOC is properly set up, adding a cover, etc) are few and easy.
There is a Word plug-in that is designed to convert Word files to MS Lit, another e-book format. However, most users have reported problems with the process, usually resulting in bad e-books, so I can't recommend it.