Well. If you have a website designed to work well on Internet Explorer and trust me there are websites of that kind or if you are a developer who wants to check how it looks and works in Internet Explorer then this can do.
IETab works on Firefox 3.0 and higher. If you are still running and older version of Firefox, it is time you upgrade. No just for this add-on for general performance and security in general.
click here to install IETab Addon for Firefox.