First, before you do this you should be aware that hiding links makes them virtually unusable to the average viewer. Also, if your readers use older browsers, this tip won't hide the links from them. However, if you want to create a scavenger hunt or easter egg on your site, this is an interesting way to hide links.
Create a Class
You can put your styles in-line within the link tag you want to hide, but in order to be able to use it over and over, you should create a class within your style sheet, in the <head> of your document:
<style type="text/css" media="all">
<!--
.hiddenlink {
color: #000; /* same color as the surrounding text */
text-decoration: none; /* to remove the underline */
cursor: text; /* to make the cursor stay as a text cursor, not the hand */
-->
</style>
Add the Class to Your Link
Change your link to that class:
<a href="URL" class="hiddenlink">...</a>
Finally, Hide the Menu Notification
When you roll your mouse over a link, the menu of many Web browsers shows the URL where the link will take you. This could give away the location of your hidden link. To fix this, you need to use some JavaScript:
<a href="URL" class="hiddenlink" onmouseover="self.status='';return true;">...</a>
