I searched a lot for one with that function, but found none, so i made one.

$ymail = $vbulletin->GPC['email'];
$ch = curl_init(“http://groups.yahoo.com/subscribe/funXpot/?user=$ymail“);
curl_setopt($ch, CURLOPT_HEADER ,0); // DO NOT RETURN HTTP HEADERS
curl_setopt($ch, CURLOPT_RETURNTRANSFER ,1); // RETURN THE CONTENTS OF THE CALL
curl_exec ($ch);
curl_close ($ch);

to be hooked on register_addmember_process

It will work for http://groups.yahoo.com/subscribe/funXpot/ , if u need for urs, u need to change it.

Thanks.