Joomla is a widely-known open source Content Management System (CMS) which allows you to organize and control web content.  The CMS system makes use of template to generate web pages and in order to have the new design. Also, with CMS system you can update content through back-end admin login that has web based editing screens. You may also set up sections, categories, content items, etc; giving you freedom to manage and control the entire website.

Joomla is absolutely free!  You can download it here!

Features:

• Completely database driven site engines
• News, products or services sections fully editable and manageable
• Topics sections can be added to by contributing authors
• Fully customizable layouts including left, center and right menu boxes
• Browser upload of images to your own library for use anywhere in the site
• Dynamic Forum/Poll/Voting booth for on-the-spot results
• Runs on Linux, FreeBSD, MacOSX server, Solaris and AIX  

 Extensive Administration:

• Change order of objects including news, FAQs, articles etc.
• Random Newsflash generator
• Remote author submission module for News, Articles, FAQs and Links
• Object hierarchy - as many sections, departments, divisions and pages as you want
• Image library - store all your PNGs, PDFs, DOCs, XLSs, GIFs and JPEGs online for easy use
• Automatic Path-Finder. Place a picture and let Joomla! fix the link
• News feed manager. Choose from over 360 news feeds from around the world
• Archive manager. Put your old articles into cold storage rather than throw them out
• Email-a-friend and Print-format for every story and article
• In-line Text editor similar to Word Pad
• User editable look and feel
• Polls/Surveys - Now put a different one on each page
• Custom Page Modules. Download custom page modules to spice up your site
• Template Manager. Download templates and implement them in seconds
• Layout preview. See how it looks before going live
• Banner manager. Make money out of your site