mauried,
the thing about buying them is it will be cheaper in the long run when these modules go for sale. before you ask why I am making it then and don't know how to make the RF portion. My friend owns a software that he wrote in java called jarvis. It is not commmands it actually can understand anything. free speech to the program and it can figure out what your asking and do it. He is busy with college, and I am new to electrical engineerings (I guess electronics would be correct as well). I wanted to learn more about RF so I offered to try to build it. It would be cheaper to design it on board with the relay and all the rest of the components. It is a small 1 relay board where you can plug in appliances etc and you can tell jarvis to turn them off and on and it can do it through the arduino. So it's really just going to be a relay board with on-board custom RF receiver and the arduino will have the transmitter. I couldn't find any tutorials online for how to build a simple rf trans and rec. with gnd, vcc, data line, and ANT (which I am not sure exactly what ANT is. I am assuming its not the java extension for apache web server). Also if it helps to know I have my CCNA as well so I know the basics of networking, OSI layers, diff types of mediums and all that good stuff.