Note - This document refers to connecting a Mac to an ethernet point in a staff office, it does not describe how to use the numerous docking points around campus or in the halls - for that information go here.
In order to successfully connect you need the following pieces of information:
Before you can access the University network, your Mac must be registered. To do this, please contact your local computing officer.
Select System Preferences from the Apple menu.

Select Network from the Internet & Network section.
Continue by selecting Ethernet, from the list of ports, then set the Mac to Configure it's IP address Using DHCP as shown below.

You now need to set some proxies so click the Advanced... button followed by the Proxies tab.
Firstly set both the Web Proxy (HTTP) and Secure Web Proxy (HTTPS) to wwwcache.ncl.ac.uk port 8080 as shown below:

Set the SOCKS Proxy to socks.ncl.ac.uk port 1080

Finally select OK then hit Apply to confirm the changes - your Mac should now be set up correctly.