Integrating vBulletin accounts with other php application user accounts?
 

I'm developing a web application that I want to have an accompanying message board. Is it possible to integrate my user accounts for my web application with vbulletin's user accounts? Specifically I want to be able to do two things:

1. Not require the user to create separate user accounts -- their account for my website will create the vBulletin account.
2. Not require the user to login separately to vBulletin -- if they login to my website, they should get logged into the vBulletin forum.

I want to do this for a few reasons, but the main one is to encourage forum participation by making it easier for users of the website to jump right into the forums if they wish. I couldn't find any clear answers about how easy this is to do with vBulletin? Is this functionality built in, or can it easily be added?

Thanks for any information you can provide on this.