Twitter tool TweetingMachine lets users unfollow users not following them back, schedule tweets, tweet website feeds, upload tweets in bulk, auto follow new followers and much more.
Best Twitter tool I have used so far. I love the unfollow feature for I get to see who is not following me back and pay them back fairly. The ONLY "bad" thing with TweetingMachine is that its very cheap compared to other services I have used :-) I love it!!