Fangs is a Mozilla Firefox extension that displays a text representation of a web page similar to how a screen reader would read it. This helps web developers finding accessibility issues at an early stage in the UI development process. A Must have for developers in my opinion, such extension is very useful for testing your website, it gives an excellent idea on how it will look on text browsers such lynx.
http://firefox.phpmagazine.net/upload/2006/02/fangs-thumb.jpg