Turn Lights On/Off Without Having to Hit 3 Switches in One Room
In my experience, Lutron Pico/Maestro line of remote switches work very well and aesthetically very pleasing.  I would not use nor recommend any other. 

In my area Home Depot sells them in white.  For more colors choices you'd need to go through an authorized dealer i.e. a lighting design center or search the internet for availability.