Output HTML code
Display a html link::

echo l(t('Edit'), "admin/settings/locale/string/edit/$lid");


Display a menu:

$menu = menu_navigation_links("menu-name");
print theme('links', $menu, array('class' => 'links menu_name'));

Display a | seperated menu:

$menu_links = menu_navigation_links("menu-name");
foreach ($menu_links as $item) {
$links[] = l($item['title'], $item['href']);
}
print implode(’|‘, $links);


Display a table:

$result = db_query('SELECT * FROM {table_name} WHERE ...');
$header = array(t('Field 1'), t('Field 2'), t('Field 3'), array('data' => t('Operatons'), 'colspan' => '2'));
$rows = array();
while ($row = db_fetch_object($result)) {
$rows[] = array(
$row->field1,
$row->field2,
$row->field3,
l(t(’edit’), “admin/content/edit/$row->field1″),
l(t(’delete’), “admin/content/delete/$row->field1″));
}
echo theme(’table’, $header, $rows);


Display a Form:
See From Programming in Drupal Way

Determine whether the user has a given privilege

if (user_access('administer nodes')) {
......
}


Options/Settings
Get settings:

echo variable_get($name, $default);


Save Settings:

system_settings_form($form);