There is a new BlackBerry Twitter Application on the block with a familiar name.  Seesmic , the popular desktop Twitter client is now available for BlackBerry devices running OS 4.6 and higher. I’ve only had the opportunity to play around with Seesmic for BlackBerry for a short while, and, even though currently in beta (alpha for the Storm, Storm2, and Tour), Seesmic for BlackBerry is a pretty nifty BlackBerry Twitter client and has a many of the bells and whistles of other BlackBerry Twitter clients currently available

See the article here:
Seesmic Launches Twitter App For BlackBerry