Tweechme is a great new partnership between Crescerance.com and Susan M. Bearden. Together they created an app that helps new people learn about Twitter. It is geared towards educators. It provides a list of the known scheduled chats. That alone would make it worth the $0.99. Beyond that, there are a series of videos by Ms. Bearden that walk us through the process of learning and contributing in the Twitterverse.
If you are thinking about Twitter, or even consider yourself a Twitter Veteran, I encourage you to give it a try.
Platform(s): iOS, Android, Windows Mobile
Cost: $0.99 (Be aware you will need to purchase separate copies for iPhone and iPad)