I have no idea if this has been done before, I haven't had time to catch up on use.perl for over a month
Firebird has a neat little search box at the top right of its UI. The content of what appears there is controlled by what's in $FIREBIRD_DIR/searchplugins. You can add as many as you want, using a really weird (but usable) syntax. It comes with Google and DMOZ (clicking on the icon in the box allows you to choose the one you want).
I added a CPAN search one. You can grab it from http://expway.com/robin/mozilla/CPAN.src along with its icon http://expway.com/robin/mozilla/CPAN.gif. Drop those in the aforementionned folder, restart Firebird and voilà! you can search CPAN. The icon is the book that does the A in the CPAN logo, credit goes to whoever did that.