Change Drupal Theme Based On URL Path
You could spend 9 years looking for a module to do it or you could do this. Put this in your settings.php
$THEME_URLS = array(
array('/admin','garland'), # Drupal already support admin theme anywho
array('/users','fancy_user_theme'),
array('/forum','forums_theme'),
);
foreach ( $THEME_URLS as $info)
if ( strpos($_SERVER['REQUEST_URI'],$info[0])===0)
$conf['theme_default'] = $info[1];
http://mattshaw.org/news/change-drupal-theme-based-on-url-path/