Perl::Critic static code for Perl based on Perl Best Practices

Check out the Perl::Critic module.
It claims to do "Critique Perl source code for best-practices ".
The best-practices are a-la Damian Conway's book "Perl Best Practices"

There's also a web service at: http://perlcritic.com/

FireBug for FireFox

There's a nice addon/plugin for FireFox called FireBug, which can be used in order to get a nice view on the source of the current page that you're viewing, including HTML, CSS, JS, network statistics, including debugging, and a few more features.

See: http://www.getfirebug.com/