Twitter Guide Book – How To, Tips and Instructions by Mashable

But where’s the user manual for Twitter? Where do new Twitter users go to learn about Tweeting, retweets, hashtags and customizing your Twitter profile? Where do you go if you want to know all about building a community on Twitter, or using Twitter for business? How can you find advanced tools for using Twitter on your phone or your desktop? To answer all these questions and more, we’ve assembled The Twitter Guide Book, a complete collection of resources for mastering Twitter.
(Link: Twitter Guide Book – How To, Tips and Instructions by Mashable)