Follow me on my twitter account:
http://twitter.com/bashscriptsTweet from your bash shell.
Change USERNAME and PASSWORD of course

Code:
#!/bin/bash
# tweet. Crouse's bash tweeter for twitter.
read -p "Enter Your Tweet: " TWEET
countme()
{
count=`echo "$TWEET" | wc -m`;
[[ $count -gt 140 ]] && echo "Tweet is $count characters, the maximum is 140 characters! Your TWEET was NOT sent!" && exit
}
countme
echo "SENDING ...."
curl -u USERNAME:PASSWORD -d status="$TWEET" http://twitter.com/statuses/update.xml -o /dev/null
echo "SUCCESS ! Your tweet was tweeted."
exit 0