What I do is simply surround the whole viewonline box with a user logged in switch.
In index_body.tpl find
Code:<br />
<table width="100%" cellpadding="2" cellspacing="1" border="0" class="forumline">
<tr>
<td class="cat" colspan="2"><a href="{U_VIEWONLINE}">{L_WHO_IS_ONLINE}</a></td>
</tr>
<tr>
<td class="row1" rowspan="3"><img src="templates/Able2Know/images/whosonline.gif" alt="{L_WHO_IS_ONLINE}" width="46" height="30" class="imgfolder" title="{L_WHO_IS_ONLINE}" />
</td>
<td class="row1" width="100%"><span class="gensmall">{TOTAL_POSTS}<br />
{TOTAL_USERS}<br />
{NEWEST_USER}</span></td>
</tr>
<tr>
<td class="row1"><span class="gensmall">{TOTAL_USERS_ONLINE} [ <strong>{L_WHOSONLINE_ADMIN}</strong>
] [ <strong>{L_WHOSONLINE_MOD}</strong> ]<br />
{RECORD_USERS}<br />
{LOGGED_IN_USER_LIST}</span></td>
</tr>
<tr>
<td height="20" class="row1"><span class="gensmall">{L_ONLINE_EXPLAIN}</span></td>
</tr>
</table>
replace with
Code:<!-- BEGIN switch_user_logged_in -->
<br />
<table width="100%" cellpadding="2" cellspacing="1" border="0" class="forumline">
<tr>
<td class="cat" colspan="2"><a href="{U_VIEWONLINE}">{L_WHO_IS_ONLINE}</a></td>
</tr>
<tr>
<td class="row1" rowspan="3"><img src="templates/Able2Know/images/whosonline.gif" alt="{L_WHO_IS_ONLINE}" width="46" height="30" class="imgfolder" title="{L_WHO_IS_ONLINE}" />
</td>
<td class="row1" width="100%"><span class="gensmall">{TOTAL_POSTS}<br />
{TOTAL_USERS}<br />
{NEWEST_USER}</span></td>
</tr>
<tr>
<td class="row1"><span class="gensmall">{TOTAL_USERS_ONLINE} [ <strong>{L_WHOSONLINE_ADMIN}</strong>
] [ <strong>{L_WHOSONLINE_MOD}</strong> ]<br />
{RECORD_USERS}<br />
{LOGGED_IN_USER_LIST}</span></td>
</tr>
<tr>
<td height="20" class="row1"><span class="gensmall">{L_ONLINE_EXPLAIN}</span></td>
</tr>
</table>
<!-- END switch_user_logged_in -->
Of course, the code may differ a bit depending on the template. But the idea is to just wrap it in the switches.
Now if you want the box vicible and just want to get rid of the URLs here is some code you can test.
NOTE: I am coding blind (and tired) and have not tested this code. So make sure you have backups and it's probably best to test on a test install. Let me know if there are any problems.
in index.php find
Code: 'NEWEST_USER' => sprintf($lang['Newest_user'], '<a href="' . append_sid("profile.$phpEx?mode=viewprofile&" . POST_USERS_URL . "=$newest_uid") . '">', $newest_user, '</a>'),
replace with
Code: 'NEWEST_USER' => sprintf($lang['Newest_user'], $newest_user),
in includes/page_header.php find
Code: $user_online_link = '<a href="' . append_sid("profile.$phpEx?mode=viewprofile&" . POST_USERS_URL . "=" . $row['user_id']) . '"' . $style_color .'>' . $row['username'] . '</a>';
replace with
Code: $user_online_link = $row['username'];
find
Code: $user_online_link = '<a href="' . append_sid("profile.$phpEx?mode=viewprofile&" . POST_USERS_URL . "=" . $row['user_id']) . '"' . $style_color .'><i>' . $row['username'] . '</i></a>';
replace with
Code: $user_online_link = '<i>' . $row['username'] . '</i>';
I think this will affect the viewonline.php page as well. Like I said be careful with the above code. I just did a quick job with no testing and there could be typos.