How do I display a user specific content?

I had coded something like this a while back and i remember wanting to upload it to the plugin repository but never had the time, Basically it adds a meta box to the post or page edit screen and lets the user select specific users by name or roles and then it check using the_content filter, so here you go:

Update:

It just got approved in to WordPress plugin repository so you can download it User specific content form there or from your dashboard and i wrote a little about it here.

<?php
/*
Plugin Name: User Specific Content
Plugin URI: http://en.bainternet.info
Description: This Plugin allows you to select specific users by user name, or by role name who can view a  specific post content or page content.
Version: 0.1
Author: Bainternet
Author URI: http://en.bainternet.info
*/

/* Define the custom box */
add_action('add_meta_boxes', 'User_specific_content_box');

/* Adds a box to the main column on the custom post type edit screens */
function User_specific_content_box() {
    add_meta_box('User_specific_content', __( 'User specific content box'),'User_specific_content_box_inner','post');
    add_meta_box('User_specific_content', __( 'User specific content box'),'User_specific_content_box_inner','post');
}

/* Prints the box content */
function User_specific_content_box_inner() {
    global $post,$wp_roles;
    $savedroles = get_post_meta($post->ID, 'U_S_C_roles',true);
    //var_dump($savedroles);
    $savedusers = get_post_meta($post->ID, 'U_S_C_users',true);
    //var_dump($savedusers);
    // Use nonce for verification
    wp_nonce_field( plugin_basename(__FILE__), 'User_specific_content_box_inner' );
    echo __('Select users to show this content to');
    echo '<h4>'.__('By User Role:').'</h4>';
    if ( !isset( $wp_roles ) )
        $wp_roles = new WP_Roles();
    foreach ( $wp_roles->role_names as $role => $name ) {
        echo '<input type="checkbox" name="U_S_C_roles[]" value="'.$name.'"';
        if (in_array($name,$savedroles)){
            echo ' checked';
        }
        echo '>'.$name.'    ';
    }
    echo '<h4>'.__('By User Name:').'</h4>';
    $blogusers = get_users('blog_id=1&orderby=nicename');
    $usercount = 0;
    foreach ($blogusers as $user) {
        echo '<input type="checkbox" name="U_S_C_users[]" value="'.$user->ID.'"';
        if (in_array($user->ID,$savedusers)){
            echo ' checked';
        }
        echo '>'.$user->display_name.'    ';
        $usercount = $usercount + 1;
        if ($usercount > 5){
            echo '<br/>';
            $usercount = 0;
        }
    }
    echo '<h4>'.__('Content Blocked message:').'</h4>';
    echo '<textarea rows="3" cols="70" name="U_S_C_message" id="U_S_C_message">'.get_post_meta($post->ID, 'U_S_C_message',true).'</textarea><br/>'.__('This message will be shown to anyone who is not on the list above.');
}


/* Save Meta Box */
add_action('save_post', 'User_specific_content_box_inner_save');

/* When the post is saved, saves our custom data */
function User_specific_content_box_inner_save( $post_id ) {
    global $post;
      // verify this came from the our screen and with proper authorization,
      // because save_post can be triggered at other times

      if ( !wp_verify_nonce( $_POST['User_specific_content_box_inner'], plugin_basename(__FILE__) ) )
          return $post_id;

      // verify if this is an auto save routine. 
      // If it is our form has not been submitted, so we dont want to do anything
      if ( defined('DOING_AUTOSAVE') && DOING_AUTOSAVE ) 
          return $post_id;
      // OK, we're authenticated: we need to find and save the data
    $savedroles = get_post_meta($post_id, 'U_S_C_roles',true);
    $savedusers = get_post_meta($post_id, 'U_S_C_users',true);
    if (isset($_POST['U_S_C_roles']) && !empty($_POST['U_S_C_roles'] )){
        foreach ($_POST['U_S_C_roles'] as $role){
            $new_roles[] = $role;
        }
        update_post_meta($post_id, 'U_S_C_roles', $new_roles);
    }else{
        if (count($savedroles) > 0){
             delete_post_meta($post_id, 'U_S_C_roles');
        }
    }
    if (isset($_POST['U_S_C_users']) && !empty($_POST['U_S_C_users'])){
        foreach ($_POST['U_S_C_users'] as $u){
            $new_users[] = $u;
        }
        update_post_meta($post_id, 'U_S_C_users', $new_users);
    }else{
        if (count($savedusers) > 0){
             delete_post_meta($post_id, 'U_S_C_users');
        }
    }
    if (isset($_POST['U_S_C_message'])){
        update_post_meta($post_id,'U_S_C_message', $_POST['U_S_C_message']);
    }
}

add_filter('the_content','User_specific_content_filter');
function User_specific_content_filter($content){
    global $post,$current_user;

    $savedroles = get_post_meta($post->ID, 'U_S_C_roles',true);
    $run_check = 0;
    $savedusers = get_post_meta($post->ID, 'U_S_C_users',true);
    if (!count($savedusers) > 0 && !count($savedroles) > 0 )
        return $content;

    if (isset($savedroles) && !empty($savedroles)){
        foreach ($savedroles as $role){
            if (current_user_can($role)) {
                return $content;
                exit;
            }
        }
        //failed role check
        $run_check = 1;
    }
    if (isset($savedusers) && !empty($savedusers)){
        get_currentuserinfo();
        if (in_array($current_user->ID,$savedusers)){
            return $content;
        }
            //failed both checks
        return get_post_meta($post->ID, 'U_S_C_message',true);
    }
    return $content;
}
?>