http://www.pcmag.com/article2/0,4149,646316,00.asp
http://www.mailgate.org.uk/uk/uk.com.../msg04955.html
http://www.firewalls.com/default.asp?ref=findwhat
http://www.zywall.com/index_zywall.php

more Hardware Firealls Recommendations here :

http://www.sperrinnetworks.com/Hardware_Firewall.html

Why hardware firewalls aren't anought ?

http://aroundcny.com/technofile/texts/giz073102.html