In a move that marks the obvious expansion of the limited preview of the February-introduced “Twitter for BlackBerry” app, Research In Motion (RIM) and Twitter announced the public beta of the application on April 8.

While the “Twitter for BlackBerry” app is a clear indication that the microblogging site Twitter is attempting to strengthen the mobile version of its site; the move also reflects that RIM is looking to give its business a boost, especially in the face of cut-throat competition from Google Android and the Apple iPhone.

Noting that the “Twitter for BlackBerry” application keeps users updated on new tweets and reply/mentions, Kevin Thau – from the mobile products and partnerships team at Twitter – said that the “free” app had been developed jointly by Twitter and RIM.

In an official blog post, Thau said: “When you talk about messaging and mobile phones, BlackBerry immediately comes to mind and it was no surprise to us that it has become one of the most popular mobile platforms for Twitter around the world.”

The key features of the “Twitter for BlackBerry” app include real-time push of Twitter direct messages; browser incorporation for Web links in “tweets;” and acknowledgment of Twitter @usernames associated with the users’ profiles and a search engine

In addition, the app boasts a multilingual interface - in English, French, Spanish, German, Italian, and Brazilian Portuguese – whose look as well as feel can be customized by the users.