There is a book of songs from Ally McBeal titled, "For Once In My Life" with the same photo on the cover as the CD with the same title. It does contain "Snakes" along with "Chances Are" and 14 others that were played/sung on Season 4.
I think I may have ordered this from the address below but you should check your local music store first. Hope you find it.
International Music Publications Limited
Griffin House, 161 Hammersmith Road
London W6 8BS