Firefox 3.1 Beta 1 is now available for download and if you would like to test the beta version Firefox 3.1, then you can head over here to download it.

This release is focused on gathering feedback regarding various features of Firefox 3.1.

The features for which Mozilla plans to gather feedback are:

• Better web standards support in Gecko - the rendering engine behind Firefox
• Support for CSS 2.1 and CSS 3 standards
• Greater control over Smart Location bar allowing you to restrict your search using special characters.
• Tab-Switching shortcut(Ctrl+Tab) that shows preview of the tab we’re switching to.
• Support for Web Technologies like Geolocation API, SVG transforms.
• New JavaScript engine - TraceMonkey that boasts of speeding up javascript rendering on a web page. You can enable it by setting value of javascript.options.jit.content to true in about:config as it is not enabled by default.

Though, Mozilla announced to have a private browsing mode in Firefox 3.1, yet it is not available in this beta release.

Full list of features to be added to Firefox 3.1 are available here.