Bruce Perens (who did Busybox and Debian as well as defining "Open Source") has created an Open Hardware Journal (http://openhardware.org/journal/). Check out the first issue, I've got two articles in it! Ok ok, probably he needed more submissions which is why my stuff made the cut :-). But hey I'll take it!
The first article "An Open Hardware Platform for USB Firmware Updates and
General USB Development" is about the USB interface on the Lightuino. I chose that topic because this interface is a cheap and tiny way to put USB in many of your projects. The interface will talk SPI to your uP or some SPI chip, or I2C (although I did not use that in the Lightuino). And it will do serial (USB CDC ACM if you need the formal acronym) or emulate an input device (USB HID). Read the article for more info, and check out my code on github here: https://github.com/gandrewstone/toastedCypressUsb
My second article "A Return To Open Devices" is about my ideas around the philosophy and driving forces behind the open hardware movement. I'm sure the people who come to open hardware do it for many different reasons; this is simply my perspective.