Can be cut to any size. 

This is a 6-pin female header, with extra long legs -- great for stacking Arduino shields.

This is a 10-pin socket with 2mm pitch that mates with the popular XBee radio from Digi. Use this small part to avoid having to solder your precious radio to a PCB. You'll need two of these sockets to connect to all 20 pins on the XBee.