
Today Mozilla released an upgrade from Firefox 5.0.1 to Firefox 6.
What’s new in this version of Firefox?
You Have More Control Over Permissions
This mean browsing data, including cookies, passwords and location information are now managed by a site-based interface Data Management Windows to let you control how much they can use. You can try out this new feature by type in your address bar: about: permissions

Firefox 6 has Faster Startup Times
This is not the rumor but it’s the truth because I’ve just tried it myself. So fast launching from blank or with some pages to open, they’re as fast as the same.
Firefox 6 Promise Faster Performance on Linux
This I cannot tell by now because I use Windows, but I believe Mozilla has made the improvements for Linux fans
Firefox 6 also said to have better Plugin Management and support HTML5 better:
Well, I heard of the Aurora version of Firefox 6 supports a great number of new features for developers, including increased support for HTML5, DOM level 3. That’s what I will experience now.
URL
Another reason of upgradation of firefox is the way of displaying the URLs in the address bar of browser. The domain name will be highlighted in the address bar,so that it is easy for you to know which website you are visiting.
E.g-http://searchdaily.net/software/updatesoft/firefox-6-update.html
As you can see from above…domain is more distinct than the rest of the address.
This is the same feature that Google and Microsoft are having for their web browser Chrome and Internet Explorer respectively for some time.
It is very valuable for spotting if users have any doubt about the URL,as sometimes a user can click on a fraudulent link in a phishing message.
Scratchpad:
There is a completely new feature in the latest upgrade of firefox called Scratchpad.It is very useful upgrade for developers.It provides a new way to test JavaScript Code.Basically,it is a simple text area in which a user can enter JavaScript Code,and then run it against the current page.You can save or open the script from scratchpad.You can also create your own collection of user scripts.

You can get the latest version of Firefox for Windows from here and for others (For Mac, Linux…) please visit this post, I also keep it updated