The client enables BlackBerry users to tailor the way @replies and direct messages are pushed to their device, and new messages are sent in real-time so that users can respond instantly.
The app also provides notice of tweets and re-tweets, allows users to search Twitter for keywords, and the layout has been optimised for the smaller screens on BlackBerry devices. Links are automatically shortened without the need to visit a third-party site.
The free app runs in the background, allowing BlackBerry users to continue checking emails or surfing the internet while still sending and receiving tweets. Users can also build, view and edit Twitter lists, and take and share photos using their BlackBerry's built-in camera.
There is currently no support for trending topics, but Research in Motion said it hoped to add this feature in time for the client's full release in the coming months.
Mobile phones are becoming an increasingly popular way for users to update their Twitter accounts and share links and photos. Many of the main mobile platforms, including Google Android devices and the Apple iPhone, also offer bespoke Twitter clients.
source : http://www.telegraph.co.uk/technology/blackberry/7572433/Twitter-app-launched-for-BlackBerry-handsets.html