Build your web applications quickly and easily using the industry leading web application IDE -- Aptana Studio

Aptana Studio is a complete web development environment that combines powerful authoring tools for HTML, CSS, and JavaScript, along with thousands of additional plugins created by the community.

Aptana Studio's editors provide world-class HTML, CSS, and JavaScript code completion, reference, and validation at your fingertips.

Get unrivaled support for popular libraries including jQuery, Prototype, YUI, dojo, Ext JS, MooTools, and others.

Add powerful plugins and ready-to-use runtimes for Ruby on Rails, Python and PHP. Eclipse users can easily add Studio as a plugin.

Use your skills to create desktop web applications with our plugin for Adobe AIR.

Download Aptana Studio for Windows, Mac, or Linux. Both the standalone and Eclipse plugin distributions are free, open source software.

Multi-browser previews, SQL database tools, an awesome JavaScript debugger, server tail views, and tons more.

for more info about this program : check out  http://www.aptana.org/