RIM on Monday announced that registered users of its BlackBerry Beta Zone can download beta 1.9 of Facebook for BlackBerries. The social networking software has seen a significant overhaul, with four major changes.

First, RIM created a dedicated inbox for Facebook. Facebook 1.9 offers two different ways for users to view their Facebook missives. The "Facebook Messages" view allows users to see only their Facebook messages in one, separate email inbox. By giving Facebook messages their own inbox, users will be able to more easily scan their inbox for important communications.

Facebook 1.9 also allows users to set it up so that Facebook messages will appear with their regular email in their main inbox. The application automatically fetches the most recent 30 email threads and sticks them in your BlackBerry inbox.

The inbox feature now also fully syncs with the online version of Facebook. This means that when a user reads a message on their BlackBerry, it is automatically marked as read in their Facebook inbox, too.

Next, RIM has refreshed the Facebook search function. According to RIM, in Facebook version 1.9 users can use the Facebook Search function to scour for individual people and pages. Once results are generated, users will also be able to view mutual friends, enlarge profile photos, and send friend requests (depending on privacy settings).

RIM has also made changes to the user interface of the application to make it easier to use. RIM says that it has updated the Friends List to add profile photos of friends. Last, RIM updated the navigation bar of Facebook for BlackBerry. RIM says the changes include new icons for Facebook Search and the new Message View.

Only registered users of BlackBerry Beta Zone can access this beta application. There is no cost to join Beta Zone, though RIM does expect beta testers to provide feedback on the performance of its software.

RIM said the full release of Facebook 1.9 for BlackBerry is also expected to integrate Facebook Places and more user interface adjustments.