The music used in the opening credits and interactive background on BBC's Olympic coverage is called Olympia: Eternal Flame and is a specially commissioned piece sung by the hottest new classical/opera sensations, Amici Forever. Their best selling debut album "The Opera Band" is available in most record shops (which from 26th August will include the Olympic piece as a bonus track too) and more information about the band can be found on their website: www.amiciforever.com
Hope that helps :-)