You can leave off the underlining of text links starting in version 6, forward.
The help text covers it in a section called
Changing Default link behavior
but if you cannot find it, I pasted it below. It looks complicated but if you print it out and follow it step by step it does work well. Plus it lets you change other behaviors of links once you understand the tool in greater depth.
You may like to override the default link properties on your site. This enables you to change styles such as the font or font color when you hover, or a link has been visited. This can be done with the following instructions;
Open the Style Class dialog, by selecting Style Class... from the Tools menu.
Select the style, 'Normal- no style'. This should be at the top of the list box of available styles.
Expand the edit side of the Style Class dialog by clicking the Edit >> button.
Click the Add Links button
This will create three CSS tag style classes that appear as;
<A:hover>
<A:link>
<A:visited>
These are Anchors which define the default behavior of links for your document. All text items with links will use this style unless you create a Style Class with its own link behavior. You can do that by following the above steps however you need to create and assign a Style Class to the text item and select that Style Class in the list box before you click the Add Links button.
You can now modify the links by selecting the desired link in the list box and clicking the modify button.
Tip:
To prevent unexpected results you should export your page as HTML with CSS or XHTML with CSS when using Style Class functionality.
In CSS language a class such as <a:hover> is called a pseudo-class.
See also
Changing link behavior for a Style Class