Apache::SimpleTemplate is yet another template-with-embedded-Perl package for mod_perl. It allows you to embed blocks of Perl code into text documents, such as HTML files, and have this code executed upon HTTP request. It should take moments to set-up and learn; very little knowledge of mod_perl is necessary, though some knowledge of Apache and perl is assumed.
This module is meant to be a slim and basic alternative to more fully featured packages like Apache::Embperl, Apache::ASP, or TemplateToolkit, and more of a mod_perl counterpart to JSP or PHP. You may wish to compare approaches and features of the other perl templating schemes, and consider trade-offs in funcionality, implementation time, speed, memory consumption, etc. This module's relative lack of "features" is meant to improve both its performance and its flexibility.
Apache::SimpleTemplate has no added programming syntax, relying simply on perl itself for all programming logic in the templates. It should run with a very small memory footprint and little processing over-head. Templates get compiled into perl packages (or subroutines), and the caching and preloading options can help you increace speed and reduce memory consumption. SimpleTemplate is also designed for extension through subclasses, into which you can add the functionality you want.