http://www.mat.ucsb.edu/~dano/sensors/index.php/Resources
http://www.sparkfun.com/commerce/categories.php
http://www.paia.com/touchsw.htm
http://www.mat.ucsb.edu/~jcastellanos/projects/NAP/nap.html
http://www.billbuxton.com/InputSources.html
http://www.sparkfun.com/commerce/product_info.php?products_id=741
http://autopilot.sourceforge.net/