Most dimmer switches will have the capability to be wired into two way switching so long as there is only one dimmer for that light.
The dimmers wire up the same as with a standard two way switch but the terminals all tend to be at the top of the switch (and rather small!).
The terminals are usually labelled L1 L2 and C, though there are variations.
If there is a standard dimmer already in place then there should not be a problem. If there is just a two way switch then check that the back box space is deep enough to fit in a dimmer switch. If you have normal pendants then the load can be the 250W dimmers so they should fit in a 25mm back box, some of the more higher powered dimmers need a 35mm back box to allow heat dissipation.
Some dimmers come with a spacer plate that holds the dimmer 10mm away from the wall to allow the dimmer to fit in a small back box, but this does tend to look a bit poor.