If you want to switch from PHP to Perl, you probably have to change the way you program/script. Unlike with PHP, Perl people like to seperate code and design issues by means of templates (yes, the PHP community has Smarty too now; funny, a templating language for a templating language ;-)

Instead of dumping your code in between your HTML output, you could just push the variables (output of the code) towards a template. The big advantage is that the result will be more readable, and easier to maintain.

I tend to enjoy Template Toolkit. To answer you question (how to insert a text file) based on this templating system:

[% INCLUDE announcements.txt %]
[download]

The learning curve might be a little steep, yet it's worth it, and it pays off, to continue reading the documentation.

You could also use PLP, by good fellow monk Juerd.