bti allows you to send twitter messages right from the command line. It works with both twitter.com and identi.ca. To use this program install the Ubuntu package with the same name (sudo apt-get install bti).
I was able to post a tweet message using bti within few minutes. The configuration is easy and straight forward. Have look at the bti example config file to get started quickly (/usr/share/doc/bti/examples/bti.example). The url shorting feature (with --shrink-urls option) however didn't work as intended though. Anyway its wonderful to be able to tweet from the command line, bti does have some pretty interesting features.
And don't forget to follow my tweets @playingwithsid.
About Bti micro-blogging command line tool
bti provides an easy way to send tweet messages direct from the command line or any script. It reads the message on standard input and uses the account and password settings either from the command line options, or from a config file, to send the message out.
It's primary focus is to allow you to log everything that you type into a bash shell, in a crazy, "this is what I´m doing right now!" type of way, letting the world follow along with you constant moving between directories and refreshing your email queue to see if there´s anything interesting going on.