How can I display lots of rows of information from a database in my drupal module?
If you're looking to build an HTML table then the theme_table() function will help a lot. See the docs page for full details but this is a basic example:

function MYMODULE_page_callback() {
  // Header for the table
  $header = array('id', 'name');

  // Get your data
  $data = db_query('SELECT id, name FROM {my_table}')-&gt;fetchAllKeyed();

  // Loop through the data and add rows to the table
  $rows = array();
  foreach ($data as $id =&gt; $name) {
    $rows[] = array(
      $id,
      $name
    );
  }

  // Return the themed table
  return theme('table', array('header' =&gt; $header, 'rows' =&gt; $rows));

  // You could also use:
  return array(
    '#theme' =&gt; 'table',
    '#header' =&gt; $header,
    '#rows' =&gt; $rows
  );
}