On April 9th, Twitter made the official announcement that it would acquire the popular Twitter client Tweetie and anoint it the official Twitter application for the iPhone. Using it's final app update, developer Atebits has included a little Easter Egg of sorts to whet our appetite for the upcoming unveiling of the newly branded app.
If you currently own the Tweetie app, be sure to update it now. When you go to refresh your timeline by pulling down, be sure to bring the menu down just a bit further than you're accustomed to and you'll be greeted with a little surprise. Along with this surprise, the latest update now finally brings full Foursquare integration to Tweetie allowing you to view location information from friends that have linked their Foursquare account to Twitter.
For those of you that don't currently own Tweetie, it's probably best to hold off until the update arrives. As indicated in Twitter's acquisition announcement, the new official Twitter for iPhone app will be free to use.