CGI.pm is definitely the way to go for web/cgi programming; for an explanation of why see use CGI or die;. But Perl is a rich language and is useful for a lot more than web-automation and cgi programming involves a lot of little (often annoying) details that may hamper your ability to learn the fundamentals of the language. I'd suggest picking up a good general Perl book, such as The Camel, and an introductory text like Learning Perl if you are really interested in learning Perl. Even if all you want to do is web programming, a general understanding of the language will serve you well.