Several resources come to mind. For example:

• merlyn has written some columns on the subject. You may find this and this helpful. (This is interesting, too.)

• O'Reilly's CGI Programming with Perl offers one starting place. You can find the code online, but the book is well worth the investment.

• The Perlfect Search engine is quite good.

• CPAN contains several modules of interest. Consider, for example, this search (alt.)

• Finally, there are scads of nodes related to the subject. Consider the results of this simple search: site search engine.

To paraphrase the tag line of a certain TV show, the code is out there.

--f