entry.php

<?php
class Entry {
  private $title;
  private $body;
  private $posted_at;
  private $author;

  public function getTitle() {
    return $this->title;
  }
  public function setTitle($title) {
    $this->title = $title;
  }
  /* setter/getter が続く感じ */
}

$entry = new Entry();
$entry->setTitle("title");
echo $entry->getTitle();