Well for learning Perl, there is a book which's name surprisingly is
Learning Perl ;-) I'd start with that, followed by the
camel.
I would always use a Templating System, even for smaller projects. It saves you much debugging time. And you can learn them, especially TT, rather quickly.
As you have some PHP experience,
Embedding Perl in HTML with Mason could be interesting for you. I personally prefer TT, for which I have some printable docu in PDF format on my
homepage.
The answer to your last question:
perldoc -f require
Happy coding.