I was under the impression that the SparkFun atmega328 with Arduino bootloader pre-burned was able to go into the socket on the UNO and work just like the original UNO.
The only thing to keep straight is to put the chip into the socket the correct way. Note the chip has a little tongue-shaped cutout on one end. This lines up with the tongue-shaped cutout on the socket (away from the USB connection side).
But I haven't tried mine yet. I'll try that later today too.