I've seen the ad too, the song is "down to the river to pray", which is in "o brother where art thou", which should be available from your local video shop. Failing that Brittania music co had it on offer at about £18 (on DVD only)highly recommend watching this film,can't wait for my local shop to get fed up with it not renting and sell it off cheap (which I think blockbuster are already doing)

Haven't the faintest who sings the uk ad version, but she does a cracking job, hope this helps,

cheers

bill