Web Filtering with PIX 515 ++

[bristolxyz]

I have a PIX 515. Am running multiple app servers.
What I am intrested in doing is blocking specific content or web sidtes from specific machines on my network. I have several subnets,... IE:

192.168.100.1 - 192.168.100.254
192.168.101.1 - 192.168.101.254
192.168.102.1 - 192.168.102.254
192.168.103.1 - 192.168.103.254
192.168.104.1 - 192.168.104.254
192.168.105.1 - 192.168.105.254
192.168.106.1 - 192.168.106.254
192.168.20.1 - 192.168.20.254

What I am intrested in doing is blocking specific activity from specific machines, for example:

From machine 192.168.103.45, do not allow access to instant messaging apps or ebay, etc.

I am looking into Websense and N2H2, but they are both too expensive. Is there some open source web filtering software that will work with the PIX?
I've looked into Proxy servers, but don't want to have to reconfigure any of th elocal machines. I have ample servers running WIn XP Server, etc, so server space is not an issue..


Any ideas will be appreciated,

Best regards

CTO
MSCE, CCNA, Novell, Symantec SS

 

[criticalUpdate]

it's certainly not open source but have you ever considered something like surf control?

Jeff