Alternative without addon Rated 5 out of 5 stars
for the braves:
open with WinRar /Mozilla Firefox/chrome/browser.jar
go to /content/browser/search/search.xml
open it with a text editor, find in the text "DOMMouseScroll",
delete only <<if (event.ctrlKey)>> in the "action" field,
save the file and update it in the archive.
Now you can scroll the search engines (but no loop) without pressing Ctrl on keyboard.
please update to Firefox4!