Publisher has no built in "web effects" features.
For a text color change that is a simple matter of using CSS.
The hover parameter to be exact. You can insert the CSS code for this on the
page with an html code fragment.
The code jrc posted would be fine but use only the a:hover.
The active and visited and link are already coded in the page by Publisher
based on your setting these colors under the custom color properties for the
pub doc.
These could override your css, besides you don't need conflicting or
duplicate code.
So you just insert
<style>
a.hover {color: #000000; font-family: Arial; font-weight: normal; font-size:
10pt; text-decoration:underline}
</style>
you of course customize the attributes as desired.
Color, font face, weight, size, and to underline or not.
This text hover is used on my site:
http://www.davidbartosik.com/
Now as for using buttons and swapping them that involves JavaScript. That's
more complicated. It can be done though if you know what you are doing.
First you find a script and then you insert it with a few modifications.
If you are interested in learning more about CSS and /or JavaScript then I
refer you to
http://www.davidbartosik.com/web.htm
this page on my site has articles on these and other web topics.
Some of which can be implemented in a Pub doc and some that can't.
My site uses CSS, you can view the file yourself at
http://www.davidbartosik.com/db_ss.css