Research In Motion’s long-awaited tablet, the BlackBerry PlayBook, will go on sale in the United States and Canada on April 19 at a base price of $499.

RIM said Tuesday it plans to sell the PlayBook through retailers and wireless carriers including Best Buy, AT&T, Verizon, Radioshack, Sears Canada and Wal-Mart.

The company’s news release did not set a date for the launch but Best Buy in its own statement said it has already begun accepting pre-orders for the device and would begin selling it on April 19.

The Wi-Fi-enabled PlayBook, which will compete against Apple’s iPad, will come in 16 gigabyte, 32 gigabyte and 64 gigabyte versions priced at $499, $599 and $699 respectively.

RIM announced plans to launch the long-awaited device, with a seven-inch screen, in 2010. The tablet will be able to stream a high-definition video to a television screen via a HDMI cable, while allowing users to run other applications at the same time.