The DB-Tech wireless remote switches look very similar to my Status remote switches (the remote control certainly does) so it's likely to be of similar technology.
There already exists a program for the Pi that can control these kind of remote switches using a program call pihat - http://www.raspberrypi.org/phpBB3/viewtopic.php?t=26485
It uses the same dirty hack as the poorman's Pi FM (square wave modulated) transmitter although as I understand you can also connect the TX board to the same GPIO pin as well.
As for ninjablocks webpage he appears to have omitted the fact that the GPIO input pins are 3.3v tolerant and yet has connected his RX board directly to the GPIO.
This in my opinion is a serious flaw in his design because these RX boards are powered by 5v and provide 0v / 5v TTL levels which could potentially damage the GPIO input pin.
The data transmitted from these types of devices use simple OOK (on off keying) the length of the pulse usually represents binary 0 and binary 1.
Since there's no agreed standard for representing binary data the timing can be different from brand to brand.
Fortunately pihat source code is easy to modify to adjust the pulse lengths although it does mean you'll need to sample the original remote control signal to try to faithfully recreate this on the Pi.