Two way light switching is common, but how do I setup a 3 way system so the light can be controlled from 3 places?
There might be some confusion because the type of switch you need is usually called a four-way switch in the US, and an intermediate switch in the UK. So for three or more switches to control the same lights, you need two SPDT switches on the ends, and four-way or intermediate switches in the middle. You can find the wiring diagram on Wikipedia.
Another way to do this which is definitely easier if you're retro-fitting is to use smart switches, such as Insteon or UPB switches (there are others as well, including the older X10-based products). These will allow you to connect one of these switches to the load being controlled, and then have other switches remotely control that switch (they communicate with each other either over the power lines in your house, or wirelessly).
The benefit is you don't have to run any new wiring. You can also add keypad controllers and remotes, and start having a single keypad that controls multiple lights at once, all with different levels of brightness and ramp rates (fade speeds).