If you are jumping with joy at the latest Apple iPod Shuffle with 4GB of capacity, you will need to read this. According to Engadget (through iLounge), it seems that Apple has input a hardware chip into the earpiece/headphone. It means that this iPod Shuffle would not work with any headphone or earpiece without this authenication chip.
At the moment, I don’t think you will find any third party earpiece maker with such chip. If you have those state of the art earpiece, you will need to rethink about getting this iPod Shuffle.