Possible Duplicate:
Firefox addon for searching with different search engines
By default, I can select a word/phrase, right-click and choose "Search with Google". I'd like a "Search with Wikipedia" to mimic this option, but instead of using Wikipedia's search function, I'd like to use the following search string:
http://www.google.com/search?hl=en&gl=us&q=wikipedia+%s
%s = word/phrase that has been selected
How can I get this to work?