[James Birkett]

Hey Maplr4life,
I'm not too experienced but I think that would take a hell of a lot of modifications. I think it's possible to mimic your own website login based on vBulletin logins, but I'm not sure if a reverse process is easy enough. There's a modification that uses a cookie across all domains if you use your vBulletin login as your default login.
As vBulletin uses a strong encryption method, you'd have to make your own login mimic their encryption system

PHP Code:

 md5(md5($password) + $salt) 


, and you'd have to make it direct to vBulletin's user database to retrieve the username and password. If you feel up to that, go ahead and try it