The tarball contains two main directories. You'll need a virtual host
set up something like this

<VirtualHost *>
    DocumentRoot /path/to/pastebin/public_html
    ServerName your.domain.name.com

    php_value include_path .:/path/to/pastebin/lib
    php_value register_globals off
    DirectoryIndex pastebin.php
    RewriteEngine on
    RewriteRule /([0-9]+) /pastebin.php?show=$1

</VirtualHost>