Fedora Tracker search plugin for Mozilla Firefox:

Icon  Name              Last modified      Size  Description
[<] Parent Directory - [>] fedoratracker.png 2004-10-09 12:16 423 the icon [>] fedoratracker.src 2004-11-07 12:58 760 the search plugin
This is a Mozilla Firefox search plugin for querying the index of
Fedora Core packages at fedoratracker.org. I've submitted it for 
inclusion on the Mycroft page, but it may take some time for it
to show up there. In the meantime, download the two files above
and drop them in /usr/lib/firefox-{version}/searchplugins/.

(Unfortunately, there's currently no way to do this on a per-user