If it is not for home use, I don’t think you are going to find many free options.
Have a look at the following page for instructions on how to enable and configure the Internet Explorer Content Advisor:
<a href=”http://technet.microsoft.com/en-us/library/dd361897.aspx”>Content Advisor</a>
Also, check <a href=”http://www1.k9webprotection.com/getk9/download-software.php”>K9 Web Protection</a>, which is developed by Blue Coat too, and is free for home use.
The K9 page contains instructions on how to install it and configure it, if you decide to use it.