Change search Google in Safari to use Firefox
You can create a new service with automator, use the &quot;Run Shell Script&quot; action, and use:
open -a FireFox &quot;http://www.google.com/search?q=$1&quot;
as the shell script text, then save it as &quot;Open with Firefox&quot; or whatever you like.
-or-
follow this summary from this thread:

Download and Install OnMyCommand/OMCEdit

Open OMCEdit

Click on &quot;Download Commands&quot; then &quot;Download&quot;

Go in &quot;Command Library&quot;

Choose #22 and click on &quot;Append to Command&quot;

Change the name if you want (in &quot;Command Name&quot;)

Write &quot; Top Level &quot; in location if you don't want a sub-menu, or choose a name for the sub-menu (&quot;In On My Command&quot; is the default)

Save

You're done!