Miku Hatsune is a vocaloid
singing synthesizer created by Crypton Media with the voice of an adolescant girl. She has long aquamarine hair tied in twin tails, wears a combination schoolgirl/spy outfit, and has an '01' tatoo on her arm, representing that she was the first in the 'Vocaloid 2' series.
Her voice-bank was provided by Saki Fujita. Her name comes from first (初), sound (音) and future (ミク), so 初音ミク, or Hatsune Miku, is the result.
She is one of the most popular of the vocaloids, and her character item is a leek, due to the appearance of a superdeformed version of herself spinning a leek in her cover of the Finnish song 'Ievan Polkka'.