Berg Strip on Shields

Forum 2005-2010 (read only) General Frequently-Asked Questions
3

They're also here:

http://www.nkcelectronics.com/arduino-stackable-header-kit.html

http://ebnstore.net/index.php?page=shop.product_details&flypage=flypage.tpl&product_id=11&category_id=4&option=com_virtuemart&Itemid=1&vmcchk=1&Itemid=1

and probably in many more places. Just look for stackable headers.