The Movable Type Open Source Project was announced in conjunction with the launch of the Movable Type 4 Beta on June 5th, 2007. The MTOS Project is a community and Six Apart driven project that will produce an open source version of the Movable Type Publishing Platform that will form the core of all other Movable Type products. Listed below is a comprehensive list of new features that you will find in Movable Type 4.0.

Understanding Your Blogs Better

• A completely reinvented user interface
• Built in reports on blog activity
• Integrated asset manager for uploading, reusing, and finding files like photos, audio, and video
• Blog-style presentation of your recent content is easy to skim and lets you know how your blogs are doing
• Customize MT’s entire user interface using the same MT template language that publishes your blog
• A customizable dashboard to display just the information you find valuable
• Kick-ass documentation — over 100 printed pages’ worth, with an exclusive book-length Business Blogging Guide offering details on exactly how to help your company communicate with blogs
• Powerful listing screens with quick keyboard access keys and the ability to work with multiple selections of entries, comments, or authors
• Quick Filters on every listing screen let you jump to the most-frequently-accessed views of your information

Better Publishing

• Smarter defaults throughout the system, offering more power with fewer configuration settings than MT 3.0
• A powerful and simple re-sizable WYSIWYG Editor, with automatic saving of drafts of entries and templates — never lose a half-written post again
• Built-in cross-blog aggregation: Publish pages that include data from some, all, or just one of your blogs
• The world’s smartest blog template language, with boolean logic for choosing which content to display. (”Show me posts by ‘Jane’ in the category ‘food’ with tags ‘meat NOT fish’.”)
• Live preview shows you your entry before you publish, with full fidelity to your live blog
• Smart controls like auto-complete for tags, a calendar selector for scheduling future-dated entries, and a completely redone UI for selecting and creating categories
• Support for publishing standalone pages that automatically use blog templates and designs
• Better plain-text entry with built-in support for Markdown and Textile, and conversion of MS Word “smart” quotes to HTML entities
• Even more search-engine-friendly with customizable URLs per entry, per-template, or per-page
• A simple IDE for templates, with color highlighting for editing tags and smart error reporting for template typos
• Paginated archives — easily walk your users through posts by date or author or category

Pricing: Free
Source: http://www.movabletype.org