yeah, plug the ear phones into the side audio jack
What do you mean? As in get the transmit and receive circuit to be that small? Or just make it so you can hear it only in your ear?
If thats the case then yes. Quite easily. All you have to do is de-solder the internal speaker wires, then solder a standard 3.5mm female jack into it thenget any old pair of head phones and plug them into the jack you just soldered in. Most walkie talkies will have a headphone jack already on the side of them.