I've finally hammered out a search plug-in for Firefox. Unfortunately the wait to get new plug-ins approved by Firefox is something like 8 months, so I'm just going to go ahead and put it here for those tech savvy enough to load them themselves.

UPDATE:

Yup--just figured it out. Thank god for the View Source command. Ok, just click on the link and it should add automatically to your web browser.

MANUAL OVERRIDE:

OK, if the above link didn't work, there are two components to the plug-in, the actually .src file and the image that goes with it, a .png file.

These need to be installed in the /searchplugins/ directory of Firefox. Here is where you can find the directory need. Simply download the above files into these directories and then restart. Should work....

• On Windows, this is usually "C:\Program Files\Mozilla\" and "C:\Program Files\Mozilla Firefox\" for Mozilla and Firefox users respectively. This path may vary on a per computer basis and doing a search on your computer for "Mozilla", "Firefox", "searchplugins" will help.
  
• On Mac OS X, it is usually under your Applications folder. Note for Mac OS X users: The "searchplugins" folder is within the Firefox/Mozilla Suite Applications folder (Mozilla.app or Firefox.app), but clicking on it will start the program. To open this folder and see the folders beneath: Ctrl-click "Mozilla.app" or "Firefox.app" and select "Show Package Contents". The folder should be at one of the following locations:
  

/Applications/Firefox.app/Contents/MacOS/searchplugins
/Applications/Mozilla.app/Contents/MacOS/searchplugins