Adding users programatically
 

Hello! I just purchased vbulletin which is being used to upgrade a forum that currently has 20,000,000 users.

The current site login/registration system will remain the same, so I want to be able to add users programatically when they register on the website so they can immediately be logged into forums as well.

Is there any built-in mechanisms or official plugins to accomplish this or will I be stuck using a community supplied plugin/mod ?

There is not built-in method to do this. You will need to use a bridge.

Ok you reference something called a bridge, is there any documentation on either building or using one of these "bridges" ?

There is this which you could use as an example - Integrate or bridge with MediaWiki

There may also be modifications you can use as examples. Just try a search.