You may find some of these articles useful.

Also, you can find good examples for Feedback forms in Writing CGI Applications with Perl. Another book, CGI Programming with Perl, provides some pretty comprehensive coverage of building search engines. Both books complement each other nicely and, taken together, provide you with just about everything you need to know to build good (and perhaps more importantly: secure) CGI applications.

Finally, the archives contain many nodes discussing these and similar topics.

--f