After a long, long wait, BlackBerry PlayBook users are finally getting a firmware update to PlayBook 2.0, which brings with it features that many say should have been included as part of the slate’s initial release.

The update to PlayBook 2.0 brings long-awaited features, such as an integrated email client, social integration with calendar and contact apps, BlackBerry Bridge (Bluetooth connectivity with a BlackBerry smartphone), as well as a range of Android apps that will run on the BlackBerry PlayBook.

PlayBook 2.0 is Research In Motion’s (RIM) answer to many of the criticisms leveled at the device when it was released last year. Users and reviewers were particularly disappointed in the device’s lack of a native email client. At launch, users had to access their BlackBerry email by connecting with their BlackBerry smartphone.

PlayBook 2.0 offers users the option to use a unified inbox that consolidates all messages in one place, including messages from Facebook, LinkedIn and Twitter, as well as personal and work email accounts.

An updated BlackBerry Bridge app provides a Bluetooth connection between the BlackBerry PlayBook and core apps on the BlackBerry smartphone, (BBM, email, contacts, calendar and browser) in order to let users view the content on the larger tablet display. The updated BlackBerry Bridge app also provides a new remote control feature that allows a BlackBerry smartphone to be used as a wireless keyboard and mouse for a BlackBerry PlayBook.

Perhaps the star of the show here is the ability for Android developers to easily port their apps over to run on the PlayBook. At launch, the PlayBook had a very small catalog of available apps.

RIM is touting “thousands of new apps” added to BlackBerry App World today, including a range of Android apps. The company also has added a new BlackBerry Video Store. Enhanced web browsing capabilities are also available with BlackBerry PlayBook OS 2.0.

Reports surfaced just last week that PlayBook 2.0 would not support ads for Android apps that were ported to the device. RIM responded with a clarification, saying Android apps ported to the device could use advertising services, just not RIM’s own BlackBerry ad services.

Aside from being deficient in certain features that many thought were essential for any tablet, RIM’s PlayBook received relatively favorable reviews when it launched last year. Both users and reviewers alike praised the PlayBook’s hardware and UI.

Yet sales disappointed, resulting in deep discounts of the tablet. RIM recorded a pre-tax provision in the third quarter of 2011 of approximately $485 million related to the poor sales of the PlayBook. RIM said it shipped 500,000 of the devices in the first quarter, 250,000 units in the second and just 150,000 in the third quarter.

In a press release, RIM said it believed that an increase in promotional activity would be required to drive sell-through. RIM attributed poor sales to what it called “recent shifts in the competitive dynamics of the tablet market,” as well as to the delay of the PlayBook OS 2.0 software.

The PlayBook 2.0 update is available for download now for free to all users.