Joomla! CMS - Popular, Powerful, Expansible Website System for Your Business
In a word, Joomla! is FANTASTIC. It's used to power tens of thousands of websites, from personal blogs to huge corporations. A website powered by Joomla! is self-editable, meaning that you - rather than a web designer or developer - can manage the pages (content) yourself. And because it's open source software, Joomla is free to use and is continuously developed and upgraded by hundreds of different people.
Zen Cart™ - Powerful, Flexible, User-Friendly Ecommerce Shopping Cart
Zen Cart is a free, database driven, open source shopping cart system that is probably one of the most flexible, user friendly yet powerful shopping cart programs available. Zen Cart™ is built for entrepreneurs by entrepreneurs. The program is built by programmers and designers who understand the online selling process from start to finish. Zen Cart™ has included all the necessary tools required to build a successful online store, and developers are constantly improving and upgrading the software based on users' requirements.