Federico Cargnelutti has shared a tip for Zend Framework users out there on how to squeeze the most speed out of a bandwidth reduction for your application.
Apache's mod_deflate module provides the DEFLATE output filter that allows output from your server to be compressed before being sent to the client over the network.
He shows you how to enable the mod_deflate extension for Apache, configure it to deflate some of the common extension types (html, xml, css, etc) and the code you'll need to add to your bootstrap file to gzip the contents of the response of your application.