The latest version of Firefox Beta has the following changes:

The address bar now highlights the domain of the website you're visiting
Streamlined the look of the site identity block
Added support for the latest draft version of WebSockets with a prefixed API
Added support for EventSource / server-sent events
Added support for window.matchMedia
Added Scratchpad, an interactive JavaScript prototyping environment
Added a new Web Developer menu item and moved development-related items into it
Improved usability of the Web Console
Improved the discoverability of Firefox Sync
Reduced browser startup time when using Panorama

*Mozilla Firefox 6.0 bta 1 voor Windows (Nederlands)

More downloads at the website