I found a couple of ways to update Twitter and read recent updates from the OS X command line. For instance, you can get all your tweets using the command line by using this command. (For some reason, retweets only show up as an "@" symbol, but your actual tweets will display correctly.)
curl -s http://twitter.com/your_user | grep '<span class="entry-content">' | cut -d">" -f2 | cut -d"<" -f1
curl -u your_user:your_password -d status='This is My update' https://twitter.com/statuses/update.xml
Mac OS X Hints
http://hints.macworld.com/article.php?story=20100407133009466