Site login & PHPbb

I am trying to find out how some people do this, when you enter their site you can login with user name & password, at which point when you enter the FORUM it will automatically sign you on the forum.
I have a site where you have to enter user name & password in order for your to get on it, but I would hate to have to each user relog on onto the forum once they are on the site already.

When they signup to your site, have the data load to your site database but also the corresponding table in the forum data base. Or you could have it go right to the froum, and when they login to the site, have it check in the forum table instead of the site table..

i dont know how do do it, but i think you would use sessions. to my understanding PHP has really nice session support.

sorry for the lack of info,

Ya, I think a combination of using the same table and sessions would work. I guess you need to wait for someone who knows sessions now..