If you want to
import users to JForum, then just fill the jforum_users table. For groups, it is jforum_user_groups.
On the other hand, if you want to
integrate your current user database to JForum - for example, to have a single sign on location -, then take a look at
http://www.jforum.net/doc/LoginAuthenticationIntegration
Rafael
[originally posted on jforum.net by Rafael Steil]