Firefox 1.x
Firefox 2.x
Firefox 3.0
Flock
Seamonkey
Windows
Mac OS X
Linux
"User Agent Switcher is a Firefox add-on that gives you the ability to switch the user agent of your browser on-the-fly. Although switching the user agent does not cause Firefox to render a Web page in the same fashion that your selection would display it in, it can still be useful when attempting to access sites that only allow browsers other than your own. Current options include IE7, Opera 9.25, and Netscape 4.8. Other agent strings can be manually added, assuming you have the proper values."
"The User Agent Switcher extension adds a menu and a toolbar button to switch the user agent of the browser. It is designed for Firefox, Flock and Seamonkey, and will run on any platform that these browsers support including Windows, Mac OS X and Linux."
