Member login, and Admin to member message system

Hi,

I need to plugin, to make a user/password login, Only members can see page content, frontpage will just show a welcome page and the login box, admin create users, and admin can send PM to the users, admin can have blogroll, with information for the users.

understand the site will work as a user information center, where the user, login to get the daily information both Pm’s and all users information.

Which plugin would suit this task most easy ?

jack