More of a FYI for anyone out there who wants to lock down a companies internet access.
As you may or may not be aware, there are an absolute bucket load of Web Proxies/anonymizers out there designed to make surfing safer (or so some of them claim)
Well if you implement a proxy based web filtering system for a company, you may find your users will use these web proxies to get past it.
This is not so much of a problem if you implement a hardware/device based filtering system as these tend to scan the traffic rather than block based on text/URL. (EG SonicWall Enhanced OS, Marshal's 8e6 Proxy Blocker)
If you have this setup and you find that people are by-passing the setup then you have 3 options:
1. Add as many web proxies as you can to a blocked sites list (a never ending task as new sites are created around the clock)
2. Block all access to problem users and only allow them to access sites in a white list you create
3. Invest money into a hardware based filter (E.G. http://www.m86security.com/solutions/web_security/8e6-proxyblocker.asp)
For those who don't want to spend the money on option 3, and would rather just add the sites to a blocked list i am able to help you.
I harvested a large number of these websites today from various sites (600 and still growing). If anyone needs a copy of the list just let me know, i will be more than happy to pass it on to you.