The Nmap::Parser library provides a Ruby interface to
Nmap's scan data.  It can run Nmap and parse its XML
output directly from the scan, parse a file containing
the XML data from a separate scan, parse a String of
XML data from a scan, or parse XML data from an object
via its read() method.  This information is presented
in an easy-to-use and intuitive fashion for storage
and manipulation.

WWW: http://rubynmap.sourceforge.net/