dau.pl is a Perl script for the IRC client irssi. DAU.pm provides the core functionality of dau.pl, i.e., the text modifying part, in a Perl module for other programs to use. The dauomat is using DAU.pm, for example.
DAU.pm is written by Clemens Heidinger <heidinger@dau.pl> and licensed under the BSD license.
You can get DAU.pm in the downloads section.