Forget TwitterBerry, the latest and greatest Twitter app for Blackberry users is the brand-new Socialscope, now in alpha. SocialScope not only integrates your Twitter feed, but adds in Facebook status updates as well. When you launch the application, you're immediately taken to your friends' timeline where you'll see their avatars, latest tweet, and timestamp. Tabs at the top let you switch between your feed, Facebook, replies, and DMs, or the main SocialScope feed which includes both Twitter and Facebook combined. You can easily reply and message others as well as favorite tweets. There's also a cool option to add users from these social apps to your phone's address book.
You'll need an invite code to get in - try following @socialscope on Twitter then DM'ing a request to them.