I word, you highlight the text, then go Insert -> Hyperlink.
In html, you type:
<a href=put-your-html-file-you-want-linked-to-here> put-what-you-want-the-link-to-look-like-here </a>
In wikianswers, you just click the "external-link" button. (it looks like a globe with a paint can by it.)
If you wanted it in something else I have no idea.