Interesting. The connector means that the serial port is for the first time accessible externally, with no hacking of the Kindle required.
The PCB has to be around 1mm thick or slightly thinner, which means you need to sand down a normal board before it fits. The track spacing is 1.5mm with 1mm width tracks.
Unfortunately, the serial port is 1.8v, which is lower than my DKU-5 Nokia cable goes. I do see good (continuity) connections using this method to the Kindle, though.
Above is a picture of the serial connector - it connects as follows: