[Xenon]

without some experience in php and mysql you won't be able to do so.

well i can tell what was done on vb.org while it was splited from vb.com

make a dump of all thread where forumid was hackforum id
make a dump of all posts belonging to that threads
inserting threads/posts into vb.org db
set thread.postuserid and post.userid = 0

changing register.php when a user registers it updates the postuserid and post.user id of all posts where username = new username.

that's the theory, now feel free to write the scripts around