I was setup Drupal (CMS) in free hosting 000webhost.com and one option from Drupal are Clean URLs. But in first time after install completed, I can not enable Clean URLs. After search in forum of 000webhost.com (by Google search), I found the trick to enable Drupal Clean URLs Step 1. Disable 000webhost analytics (here). Step 2. Edit .htaccess file in root (Drupal) directrory, by remove "#" before "RewriteBase /" in line 100 and save change (in case user Drupal 6.4). Step 3. Back to menu "Site Configure > Clean URLs" and enable, finish ! I do not know why, but it is work. Good luck.
Enable Drupal Clean URLs in 000webhost.com
2 October 2008