Discovered by Engadget, the filing reveals the device -- a Bluetooth trackpad which would allow users to control their desktop using multi-touch gestures -- has now been approved by the FCC. The FCC filing lists the trackpad as a "Bluetooth Device" which can be used by MacBooks, and features a circular bottom where batteries can be placed, and a touch-sensitive surface thought to be capable of multi-touch interactions.
Leaked images by Engadget just hours before the WWDC in June show a similar piece of hardware which has the same model number as the device in the FCC filing, suggesting the images were not in fact fake. These were also backed up by rumors floating around since late 2009 that Apple were testing a multi-touch device, which the FCC filing confirms, with the initial hardware testing occurring on the 7th of October, 2009 according to the documents.
While the name of the device, which is only called "A1339" in the FCC filings, is yet to be revealed, it's likely the device will be called (based on Apple's trademarks) the Magic Trackpad or Magic Slate, and could become available anytime from now on.