Drupal is an excellent PHP based open source content management system with a wealth of features. It allows rapid development of feature rich web sites and can easily be extended to cover a wide variety of useage scenarios from basic CMS to social networking portal, eCommerce and more.
Edmonds Commerce specialise in open source PHP development and can help you to put together the best Drupal based CMS system. If its good enough for the White House, its good enough for you.
