[Kirk Y]

Create a New Plugin using Hook Location "forumhome_start". Fill it with this:

$topposter = $db->query_first("
SELECT userid, usergroupid, IF(displaygroupid=0, usergroupid, displaygroupid) AS displaygroupid, username, posts
FROM " . TABLE_PREFIX . "user
WHERE posts > 0
ORDER BY posts DESC LIMIT 1");

$newusername = $vbulletin->userstats['newusername'];