[Choo]

In my last project I had the same task and I think I can help you.

At first you need to include global php such way (it is important):

PHP Code:

$dir = getcwd();
chdir(PATH_TO_VB);
require './global.php';
chdir($dir); 


After that you can work with vb's superobject using $GLOBALS['vbulletin'] variable. You mentioned 2 problems - last posts and authentification. OK... To get last posts you can use something like that:

PHP Code:

function get_posts($threadid)
{
    $posts = array();
    $query = $vbulletin->db->query_read("SELECT * FROM post ORDER BY dateline DESC LIMIT 10");
    while($post = $vbulletin->db->fetch_array($query)) $posts[] = $post;
    return $posts;
} 


Where $vbulletin is vb's superobject.

And now about users. Look at $vbulletin->userinfo property, it contains information about logged user.