In over a month after its acquisition of the independent iPhone-specific “Tweetie” app, from its creator Loren Brichter, Twitter Wednesday announced the official re-branding of the app as “Twitter.”

The “Twitter” app, which is a distinct “version 3.0” and is now available in the App Store, is essentially the same as the earlier “Tweetie” – thereby refuting speculations that the name change might also be accompanied by a big update that would include iPad support.

Nonetheless, some of the new features and tweaks that mark the newly-rebranded official Twitter app will allow users the advantage of using the microblogging site without an account; and the ability to sign up for a Twitter account from within the app itself – along with a Suggested User List.

In addition, the new Twitter app boasts a reorganized “More” tab and inclusion of Top Tweets in the search results. The app also includes a shift of popular actions to the main action bar.

Twitter, which had long been relying on third-party developers for the creation of Tweeting apps, has been noticeably stepping up its presence in the mobile arena. With its earlier-this-month release of the Twitter for Android, as well as RIM’s launch of its own Twitter app for the BlackBerry, official Twitter clients are now a part of the three market-leading smartphone platforms.