about:config in firefox
I just discover about:config (type it in your location bar). It is a very simple configuration editor, with user settings in bold.
For example I like to use a local google version to search (google.ch instead of google.com), so I configured browser.search.defaulturl
Neat!
I also found out recently how easy it is to edit Firefox search plugins – for example to change the Amazon.com one to Amazon.co.uk so I can actually use it. There is a “searchplugins” folder in the Mozilla Firefox installation folder (Program Files on Windows: for Mac, control-click Firefox.app and choose Show Package Contents), and this contains the search plugin definitions including amazondotcom.src. There you can just edit the action URL (and probably the name and description for consistency).
Or you could just go to http://mycroft.mozdev.org/ and get the search plugin you want.
good tip indeed!