XBees are so cute and tiny but if you're using them in a circuit you'll be annoyed to find that your classic 0.1" headers don't fit them! That's because they use 2mm spacing instead of 2.54mm spacing. That's why you need special sockets like these ones!
As of Tuesday, June 16th, 2015 they are selling two sockets together instead of just one!
These sockets have 10 pins, spaced 2mm apart. Check the datasheet for a detailed diagram. You can find a footprint for the XBee that works with this connector in Adafruit's Eagle Library (its called XBEE).