One of the few features missing on Twitter is the ability to send DMs to several people at once.
That’s why you will probably love using TweetGuru MultiDM. This free tool allows you to reach up to 12 people in one fell swoop!
Visit http://tweetguru.net/multi and log in with your Twitter credentials. On the next page, enter each @username separated by a comma in the IDs box, type your message, and click the “Send Multi DM” button.
Your recipients will receive the DM right away.