The song is Niji (虹 - "Rainbow"), by Japanese House/Trance/Technopop legend Denki Groove (電気グルーヴ), and was featured in the last episode of 2005 TV-anime Psalms of Planets Eureka seveN. This AMV is an official production and is taken directly from the bonus DVD that came with the Complete Best O.S.T. collection.