Basic Steps

If you want to help the Tor network grow and create your own proxy to use with the RoutingPacketsIsNotACrime PAC files then these instructions should get you started. If you don't already have a dedicated server consider visiting DigitalOcean, Amazon EC2 or for some really good deals check LowEndBox.com. For various reasons I would suggest hosting the server outside of the UK but that is a choice for you to make.

CentOS 6

Install EPEL

wget http://www.mirrorservice.org/sites/dl.fedoraproject.org/pub/epel/6/i386/epel-release-6-8.noarch.rpm
yum install epel-release-6-8.noarch.rpm

Edit iptables

vim /etc/sysconfig/iptables

Allow the ORPort and the proxy port (in this case 9001 and 9150)

*filter
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
-A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
-A INPUT -p icmp -j ACCEPT
-A INPUT -i lo -j ACCEPT
-A INPUT -m state --state NEW -m tcp -p tcp --dport 22 -j ACCEPT
-A INPUT -m state --state NEW -m tcp -p tcp --dport 9001 -j ACCEPT
-A INPUT -m state --state NEW -m tcp -p tcp --dport 9150 -j ACCEPT
-A INPUT -j REJECT --reject-with icmp-host-prohibited
-A FORWARD -j REJECT --reject-with icmp-host-prohibited
COMMIT

Save and quit

/etc/init.d/iptables restart

If your server has IPv6 then make similar changes to ip6tables

Editing torrc

vim /etc/tor/torrc

A minimal torrc for use with a PAC file style proxy would look similar to the below (although you should read all the options to understand what you are doing);

SocksPort xx.xx.xx.xx:9150
ORPort 9001
Nickname TheNameOfYourRelay
ContactInfo YourContactDetails
ExitPolicy reject *:*

xx.xx.xx.xx should be a routeable IP (e.g. not 127.0.0.1) of your server, if you want to keep your relay server partially private you might want to add PublishServerDescriptor 0 to your config too.

Start Tor & Confirm it is working

/etc/init.d/tor start
tail -f /var/log/messages

You should see something along the lines of;

socks Tor[31452]: Self-testing indicates your ORPort is reachable from the outside. Excellent. Publishing server descriptor.
socks Tor[31452]: Bootstrapped 85%: Finishing handshake with first hop.
socks Tor[31452]: Bootstrapped 90%: Establishing a Tor circuit.
socks Tor[31452]: Tor has successfully opened a circuit. Looks like client functionality is working.
socks Tor[31452]: Bootstrapped 100%: Done.
socks Tor[31452]: Performing bandwidth self-test...done.

Windows

Follow the tutorial on Securely Installing Tor on Windows to get the full Tor Browser bundle up and running. Once installed and started Tor will be running on localhost:9150 (do not close the Tor Browser as this will also close the relay)

Done!

Assuming you have chosen the URLs you wanted by creating a PAC file you can now browse to the URLs that were previously censored as they are now being routed over Tor. Any non-restricted URLs will route over your normal Internet connection.