There have been many warnings recently about the Firesheep add-on for Firefox that enables someone to capture users’ sign-on information when it’s sent over an unencrypted connection (such as the sign-in pages used by many popular social networking web sites). The good news is that now you can fight the add-on with an add-on; in fact, there are two available that will detect Firesheep snooping and prevent it. You can find out more about them here:
http://news.cnet.com/8301-13880_3-20022306-68.html?part=rss&subj=news&tag=2547-1_3-0-20