Outlook Today uses IE to render the HTML, all of the links in Outlook Today are affected by the way the new version of IE handles styles. IE's default setting is to underline all links if a style is not applied, but IE8 ignores the CSS Outlook Today uses for links and the links are underlined, per the default setting.

You can change the setting in IE's Internet Options but keep in mind it will apply to all HTML pages, not just Outlook Today.

From either Control Panel or IE's Tools menu, open Internet Options, Advanced tab. About halfway down the list of options, under the Browsing section, is Underline links, with three choices:
- Always
- Hover
- Never

The default selection is Always. Choose Hover or None.
Click OK to save the settings and close the dialog.

The changes take effect immediately, without restarting Outlook or refreshing the Outlook Today page.