TweetFunnel

"With TweetFunnel, managing your corporate tweeters becomes much more efficient and empowering! Staff tweeters each receive their own login to TweetFunnel and they can post their tweets to a central staging area for review. The designated corporate Twitterer then edits and releases new tweets to Twitter - either right after editing each tweet or by scheduling a "trickle" of Tweets that will post throughout the day"