If you do not have a neutral wire at the wall switch location controlling a light, this means that you have what's called a switch leg or drop.  Rather than running to the power wiring to the wall switch and then up to the light fixture(s), in this case the power is run to the fixture first, and a single pair of wires is dropped down to the wall switch.

Without a neutral it is impossible to use most automation dimmers or switches.  One solution is to use the existing wiring in the walls, adding both a wall switch or dimmer, and using an inline module at the fixture location.  You can see that no new wires need to be pulled, but rather they are used differently.

The power wiring that is coming in to the fixture, is now used to send power (hot & neutral) down to the switch location.  It also powers the inline module and the inline module now switches/dims the light.  Both Insteon and Zwave make a 'micro module' which is perfect for this purpose as it is much smaller than regular inline modules.

In the case of Insteon, one would use an Insteon link between modules.
In the case of Zwave, one would use a Zwave 'association' between modules'.

In both cases, when the wall switch is pressed, it sends a 'signal' to the inline module telling it to turn the light on/off or bright/dim.

Illustration is shown below.  Note:  Exact connections at switch/module will vary by part#, and ground wires are not shown for simplicity.  This is simply to provide an illustration of the concept.  We recommend working with an electrician on this one.

LIGHT SWITCH WITHOUT NEUTRAL	AUTOMATION USING INLINE MODULE