TweetDeck is preparing to release its first Android app in beta tomorrow. I got a hold of the beta build and some screenshots. The app adds some new elements which go beyond TweetDeck's popular iPhone app, and even introduces some new elements not yet found in its desktop app. But this app shows the direction where TweetDeck is going. As CEO Iain Dodsworth noted in a blog post yesterday that it "also represents the future of our iPhone and iPad applications." The mobile app, which is TweetDeck's first foray onto Android phones, supports multiple streams beyond Twitter, namely Facebook, Foursquare, and Google Buzz. (The desktop is also multi-stream , but the iPhone app only supports Twitter and Facebook). The biggest departure, though, is a blended stream that combines updates from all four services, color-coded with different backgrounds for each one. TweetDeck's other apps maintain a separate column for each stream.