RIM has announced that the second version of the OS for its much-maligned BlackBerry PlayBook tablet is rolling out today – chances are that it’s too late to do much good for the device’s long-term chances on the market though.

The headline feature of PlayBook OS 2.0 is an integrated email client. RIM received heavy criticism for not including a native email app with the initial launch of the PlayBook – especially as messaging is a supposed strength of the BlackBerry brand.

PlayBook OS 2.0 comes with a unified inbox that supports multiple email accounts, plus social messaging from Facebook, LinkedIn and Twitter. This social integration also extends to the Contacts and Calendar apps.

Additionally, BlackBerry App World has been updated to include a range of new PlayBook apps, including a selection of Android apps which are supported by the tablet for the first time. Support for Android is limited to say the least however.

BlackBerry Bridge, which allows PlayBook users to display apps from their BlackBerry smartphones on the tablet’s screen over a Bluetooth connection, has been updated to allow the smartphone to be used as a remote keyboard and mouse controller.

Updated document editing functions, an improved Web browser, a new Print To Go app and Video Store, and a revised on-screen keyboard are among the other updates launched with the new version of the OS.

To give the PlayBook a chance in the enterprise market, RIM has included BlackBerry Balance to manage corporate data. It’s also pushing out an initial release of BlackBerry Mobile Fusion – a Web-based interface for managing BlackBerry smartphones and tablets in a corporate environment. RIM plans to expand this to support control over iOS and Android devices next month.

BlackBerry PlayBook OS 2.0 is available as a free download today for existing users. While it definitely throws in some much-needed improvements to the tablet’s offering, it may be too late to save the reputation of the hardware itself, and its ailing manufacturer.