Still, this is not easy to realise. I will try and explain it as clearly as possible, so that anyone should arive at getting it to run. However, you should be familiar with the shell (called ‘Terminal’) – if not, start reading about it now.

So lets do it. What we need is four pieces of software. The first is Colloquy (http://colloquy.info/, which we install just the usual way in our GUI environment). Second, we need Macports (www.macports.org, which is just a software managment software. We only need it to download and install the following two programs). Third, Tor (https://www.torproject.org/, the software for connecting to proxy mixes). Fourth, Socat (http://www.dest-unreach.org/socat/, which is a software that can act as a network connections interface between other programs).

What we will build might look like the following:
(Colloquy) — (Socat) – (Tor) – (Tor Proxy)
The first three brackets show software which will run on our computer. As you can see, Socat will establish the connection between Colloquy and Tor, which will then connect to the Tor proxies on the web.

Now to the installing, configuring and running:

1. Get Macports and install it. You can get helpful info here: http://guide.macports.org/.

2. Via the shell, install Tor and Socat using Macports:
:~ sudo port install tor
:~ sudo port install socat
Both installation processes will take a while.

3. Configure and run Tor: See whether there is a file /opt/local/etc/tor/torrc. If there only is one called torrc.sample, copy it to the name of torrc:
:~ cp torrc.sample torrc
Then, run Tor:
:~ tor
The process should tell you something like:
“Tor has successfully opened a circuit. Looks like client functionality is working.”
Leave that terminal window open and get another one (cmd-n). You can stop the Tor process by ctrl-c.

4. Run Socat by entering:

:~ socat TCP4-LISTEN:6666,fork SOCKS4A:localhost:SERVERNAME:6667,socksport=9050

At the place of SERVERNAME, you have to enter the name of the IRC server you want to connect to.
Leave that terminal window open, too. You can stop the socal process by ctrl-c.

5. Configure Colloquy
Right-click in the Connections window to make a new connection. For the server name, enter ‘localhost’, and 6666 as the port number.

6. Chose that connection and click ‘Connect’. Now you should connect to the required server. Go into any room (or open one yourself), right-click on your user name and click ‘get info’ to make sure your IP and hostname are those from the Tor proxy you use (i.e. not those ones that your ISP provides you with).

See info on this issue on the web:
http://www.learnsecurityonline.com/index.php?option=com_mamboboard&Itemid=69&func=view&id=997&catid=41
http://blog.oneinsane.net/?p=14
https://wiki.torproject.org/noreply/TheOnionRouter/TorFAQ#head-1793e1e8a4701ba463b5b82b33f59e787ff752f9