Not to toot my own horn, but I will. The Teach Yourself Perl in
24 Hours (Not "21 Days"!) book has a very concise but thorough of
all of the basic CGI techniques you need. It's only $20. An
electronic edition will be available in the Linux Web Page Construction
Kit when that's published in a few months.
Sean Burke did a nice review of it on Amazon's site
(http://www.amazon.com/exec/obidos/ASIN/0672317737), it passes
the Perl Book Litmus test with ease and is generally regarded
as a decent source of clues. I use it as a textbook for teaching
Perl and CGI programming.
And if you have any questions about it, just write me. I stand
behind every word written. Even the typos. :)