CMS (Content Management System)

• MODx CMS and PHP Application Framework
• Plone CMS and content management framework that works hand-in-hand and sits on top of Zope (written in Python)
  • The Definitive Guide to Plone: A good guide to Plone though a bit outdated. It recommends to learn about Zope, TAL, Python, then Plone.
  • Plone documentation
• Joomla CMS (written in PHP)
• Drupal CMS (written in PHP)
• Spip CMS (written in PHP)

Web Framework

• Django a high-level Python Web framework
• Turbogears a rapid web development megaframework. It is based on CherryPy, SQLObject, Kid and MochiKit.
• Ruby on Rails an open-source Ruby web framework.

Web Server

• Apache: Web server
• Lighttpd: A lightweight web server
• Nginx: A high-performance HTTP server
• Varnish: An HTTP accelerator, a high performance caching reverse proxy
• Zope: An open source application server for building content management systems, intranets, portals, and custom applications

CSS/Ajax

• 24 ways : CSS Layout Starting Points
• Starting with CS: revisited - KuraFire Network
• CSS tips and tricks at The Blog Herald
• Ten more CSS tricks you may not know
  
• Web Develooper Lists : eConsultant
  
• Round-up of 30 AJAX Tutorials