Hi,
In order to do this you'll need to pass the html of the page to a pdf create program that converts html to pdf format....there are some free ones about, but integrating them into NB_Store/DNN could prove difficult and would probably require a code change.
Probably you easiest way is to integrate a print button into the template.. http://www.jquery4u.com/plugins/10-jquery-print-page-options/
Dave.