Research In Motion (RIM) announced Tuesday that its long-discussed PlayBook tablet will begin to ship on April 19, 2011, at prices starting at $499.

[ad#Google Adsense 300×250 in story]The BlackBerry PlayBook with Wi-Fi comes in 16GB, 32GB and 64GB varieties, priced at $499, $599, and $699 respectively – the same price as Apple’s similarly-equipped iPad 2.

Customers interested in the PlayBook can go to Best Buy, Best Buy Mobile or (in Canada) Future Shop stores or order them online beginning after 8 AM Eastern Time on Tuesday.

Billed by RIM as “the world’s first professional-grade tablet,” the BlackBerry PlayBook weighs 0.9 pounds and measures 5.1 x 7.6 x 0.4 inches. That’s lighter than an iPad but only about half its length. The device as a 1024 x 600-pixel resolution capacitive LCD touch screen, and is powered by a 1GHz dual processor.

The PlayBook sports 1080p HDMI output and dual cameras (3 megapixel in the front, 5 megapixel in the rear), stereo speakers and stereo mics, 802.11n Wi-Fi capability, and Bluetooth 2.1+EDR support.

Where RIM hopes to significantly differentiate its device from the iPad is support for Adobe Flash Player (version 10.1) and a user experience based around BlackBerry Tablet OS.

It’s a positive step for RIM, which announced the PlayBook in September but is yet to actually ship the product.