tircd presents Twitter as an irc channel. You can connect to tircd
with any IRC client, and tweet as if you were on IRC.  The daemon
supports authentication via OAuth or standard http and https
authentication, and supports direct messages, automatic URL shortening,
and Twitter searching.

Quickstart: in irssi, "/connect localhost 6667 twitpass twituser"
and join #twitter

    - @gavinatkinson

WWW: http://code.google.com/p/tircd/