Go to your-freedom.net and create yourself an account ( Click on "First visit? Click here to register" under login ).
NOTE It looks like registration process does not work properly with Safari. I recommend you to use Firefox instead.
Your account will become fully activated only after you have received activation e-mail from your-freedom.net and complete activation process according to instructions in that e-mail.
NOTE This step is not quite Safari friendly either. When you click on first link in the e-mail (assuming Safari is your default browser) it will open page in Safari and may complain that something is not right (it did it to me), but actually it will complete registration and you end-up been "logged in".
Go to Downloads section of web site and download client for Mac OS X. Once it downloaded mount the DMG and move client into your /Applications folder. When your run the client for first time, you will be presented with short setup wizard. Just pick all default answers and you should be fine (if you want to read documentation, you can look into user guide. it is for Windows, but it looks like process is very similar ).
Push the button ("Start Connection" on "Status" tab).
Once you have your-freedom connection started, you will have SOCKS proxy running on your local host. So configure WoW2GO to use SOCKS with "Host:" set to localhost (literally, enter 'localhost' as a host name. see wikipedia for more information about 'localhost').
NOTE you do not have to enter your-freedom user name/password into WoW2GO!!
Push "Start" or "Play" button on WoW2GO as you normally do! Enjoy!