Ok, open Boardindex.php and search for this:
<font color=\"red\">
That should bring you right to the section where you need to be, the whole thing will look like this:
if ($tmp['realName'] != '')
{
if ($tmp['memberGroup'] == 'Administrator')
$tmpusers[] = "<a href=\"$scripturl?action=viewprofile;user=$euser\"><font color=\"red\">$tmp[realName]</font></a>";
elseif ($tmp['memberGroup'] == 'Global Moderator')
$tmpusers[] = "<a href=\"$scripturl?action=viewprofile;user=$euser\"><font color=\"blue\">$tmp[realName]</font></a>";
elseif ($tmp['memberGroup'] == 'YaBB SE Developer')
$tmpusers[] = "<a href=\"$scripturl?action=viewprofile;user=$euser\"><font color=\"green\">$tmp[realName]</font></a>";
elseif ($tmp['memberGroup'] == 'Mod Team')
$tmpusers[] = "<a href=\"$scripturl?action=viewprofile;user=$euser\"><font color=\"orange\">$tmp[realName]</font></a>";
Just change that red to whatever. You'll also notice you can change the other member group colors there. I should also mention there's a mod that can make this less messy and on your menu so you can change them from the admin panel. It can be found here:
http://www.yabbse.org/community/index.php?board=158;action=display;threadid=19648Methonis