There is a pretty simple means to add a search to the Firefox search collection: (via Mike Chambers blog)

Call this javascript code from within Firefox:

window.sidebar.addSearchEngine(
"http://mesh.typepad.com/firefox/search/"+name+".src",
iconPath,
name,
cat );


where the “src” file is:

<search
version="1.1"
name="engadget"
method="GET"
action="www.engadget.com/search/">
<input name="sourceid" value="Mozilla-search">
<input name="q" user>