If you happened to be a user of Tweetie, you might find something strangely familiar in the new official Twitter app for Apple's iPhone. That's because it used to be Tweetie.According to Pocket Lint, Tweetie was bought out by Twitter last month. A shrewd move by Apple, which has tweaked a widely-used product to version 3.0 to bring in Tweetie's original audience and to pull in the punters who love anything with the word 'official' attached to it.Now available via the UK app store, it has all the mobile Twitter basics of posting, replying, sending DMs and viewing users' timelines and information, along with a more prominent 'retweet' button for those laugh out loud 140-character gems, improved search, local searching, top tweets and if you're on the look out for friends, suggested Twitter soulmates.Don't have Twitter? You can use it to browse without an account, but if you need one, you can sign up via your iPhone handset, with up to two accounts able to be used with the app. If all that has left you wanting more, head to Apple's app store to get the lowdown and the download.