Steven, those pages' language files are found in /includes/languages/english/shippinginfo.php, privacy.php and conditions.php, respectively.
When you're navigating through your store (unless you're using a URL obfuscator), the variable main_page identifies the name of the page currently being displayed. So, if your browser's address bar reads
Code:
http://www.example.com/index.php?main_page=something
then the associated English language file is present in either
Code:
/includes/languages/english/something.php
or
Code:
/includes/languages/english/YOUR_TEMPLATE/something.php
where YOUR_TEMPLATE is the name of your active Zen Cart template.