In another post, I said it would be cool if we can translate contents of different languages on a page into one language. This now has become a reality: Micah Wittman created this tool using Google translate API that makes the translation only one click away.
I have tested on other browsers but I made it work on FireFox.
On FireFox, you need first install Greasemonkey plugin. Then you go to http://wittman.org/projects/friendfeedtranslate/install/ and click on one of the 
buttons. Then an “Translate X to English (or to any other languages)” button will appear on the right top corner of your friendfeed. Click that button and all the contents on the page you are viewing will be translated into English.”
FriendfeedTranslate is part of a project called Translaterize, which also includes “Translaterize for Facebook.”