XtremeMac has announced its new Micromemo microphone accessory for the fourth-generation iPod nano. This digital audio recorder saves .wav files onto the nano, where they appear in iTunes the next time the device is connected, and is designed to complement the body of the nano, with a protective back that encases the device. Other features include a flexible, detachable microphone, illuminated recording status indicator, a built-in speaker, and a…