Although there are some legal things to achive with this hack, most of the users are pirates.
There are some sources which have the lockdownhack and the vb.zip file to download for...
If you come ove such sites using the lockdown hack, you may want to report them:
http://www.vbulletin.com/contact/piracy.php
This could help us, and if they are no pirates, no harm will happen