from another person for a site you own? I can see how purchasing an entire site including an owned VB license should be acceptable and work for all parties. How about buying just a VB license from someone else though, and then using it at one of your own domains?
It actually is much better if you ask Vbulletin/Jelsoft directly about this. They can probably check if the license is okay to be transferred and lead you the right path. http://www.vbulletin.com/contact.php
Well, I know a few people who have traded licenses. I don't know if it was actually legal and good or not, but nothing has happened as of yet. Still, as Eddy said, I suggest you take it up with Jelsoft directly.
yes u can... the members area of vbulletin allows you to transfer it over to a member of the site... so yes its all good!