I think that some bits of information you require have been given by more experienced people but here are my thoughts:

'Websites' are pretty much in HTML whether static or dynamically generated, only the source of the code changes.

Perl is good for generating dynamic content and CGI.pm is a really useful module, although the HTML language it actually generates is crufty to read (bad formatting) - fortunately browsers don't mind ;-)
It is also quite easy to learn - if you intend on using CGI a lot, the book CGI Programming with Perl is pretty good. Although, as pointed out there are online tutorials, go - here - for some given by Google.

A final note and on something I know very little about: be aware of security and safety issues - it can be quite easy to overlook something which can really give your database a bad day if you're not careful!

Hope this helped - enjoy. Elgon.

"All characters are incidental" - Kurt Vonnegut

Update: Check out this link for 'issues', many thanks to epoptai