I've noticed this connector on a lot of boards, and I was wondering if anyone knew where to source them? I can't seem to find them on digikey.com anywhere. What I'd really like is to get a male connector for this to breadboard the contacts.
To compliment Gonziks answer, another brand that is very similar is the Panasonic F4S series:
These look like Molex SlimStack 0.4mm or 0.5mm board to board interconnects (http://www.molex.com/molex/products/group?channel=products&key=slimstack). Breakout boards for these are not common. You'll have to either do a board spin or flywire 40 gauge magnet wire to interface with these.