Howtoforge posted a guide about using ngx_pagespeed with nginx On Debian Wheezy

Google has just released PageSpeed Beta for nginx, the nginx equivalent of mod_pagespeed for Apache. This module applies web performance best practices to pages, and associated assets (CSS, JavaScript, images) and therefore speeds up your web site and reduces load times. This tutorial explains how to use PageSpeed with nginx on Debian Wheezy.

  Using ngx_pagespeed With nginx On Debian Wheezy