http://forum.joomla.org/index.php/topic,37191.0.html
all addons for the connector you can find in this thread
the com_connector/ vbulletin application connector is only API for connect applications: common login, user synchronisation/management
its joomla 1.0.8 problem see supportforum for joomla
for link register on joomla to vbulletin you must edit mod_register.php file in joomlaroot/modules folder