Twitter users of both the iPhone and the even more ubiquitous Android phones can now rejoice. New and improved versions of Twitter iPhone and Android apps have just hit the app stores of those respective devices this summer. Twitter mobile apps are nothing now. Pretty much since the platform emerged, mobile users have enjoyed tweeting, retweeting and PMing their favorite celebrities, business partners, role models and friends. Now, with improved design and all new features, the Twitter iPhone and Android apps are sure to keep Twitter enthusiasts engaged.