Xibdiff is a project mainly written in Ruby, it's free.
A tool for diff'ing XIB/NIB files created in Interface Builder
== xibdiff
== DESCRIPTION:
xibdiff - a tool for diffing XIB/NIB files created in Interface Builder
== REQUIREMENTS:
== INSTALL:
$ gem install git://github.com/igorsales/xibdiff.git
== SOURCE:
xibdiff's git repo is available on GitHub, which can be browsed at:
http://github.com/igorsales/xibdiff
and cloned from
git://github.com/igorsales/xibdiff.git
== USAGE:
xibdiff <file1.xib> <file2.xib>
== LICENSE:
LGPL (The Lesser GNU Public License)