Methods and apparatus for providing controllable power via an A.C. power source to LED-based lighting devices having an MR16 configuration. In one example, LED-based MR16 lighting devices may be coupled to A.C. power circuits that are controlled by conventional dimmers (i.e, "A.C. dimmer circuits"). In yet other aspects, one or more parameters relating to the light generated by LED-based light sources (e.g., intensity, color, color temperature, temporal characteristics, etc.) may be conveniently controlled via operation of a conventional A.C. dimmer and/or other signals present on the A.C. power circuit.