List of Internet Parental Control Utilities (free to my best knowledge):

Naomi:
http://www.radiance.m6.net/oldindex.html

OpenDNS Parental Controls:
http://www.opendns.com/homenetwork/solutions/parental/

File Sharing Sentinel:
http://www.akidthaine.com/

Safe Families Parental Control:
http://www.safefamilies.org/download.php

K9 Web Protection:
http://www1.k9webprotection.com/

B Gone Parental Control:
http://support.it-mate.co.uk/?mode=Products&p=bgone


Note: If any of the freebies ever become commercial products then check for their last free version here.


Enjoy!