https://addons.mozilla.org/firefox/2207/
"--You can select and right-click on a word or phrase in your browser or preview window to automatically submit that item to a subsequent search on google, wikipedia or thefreedictionary"
"With Cooliris, there is absolutely no adware, spyware, or advertisements. Versions for Internet Explorer and Safari also available, at
http://www.cooliris.com. Previews do NOT count as clicks."