You knew it would happen sooner or later. Indenti.ca (no Canada comments) has released an open-source version of a micro-blogging tool.
Cool thing is that it sounds like they are also trying to go after the concept of federation. Think about it as a Jabber or OpenID for micro-blogging.
Very geeky, very early. Bit ironic that the lead dev/guy who started the project is named Evan.
Guess the next question is "When do we see the open source version of Facebook???"