Cold Fusion is a great language - however, IMO, PHP is so much easier and more flexible. Granted, this is prolly why you are switching.
I do not know of any utilities that will convert and to be honest, I wouldn't if I did. You will probably find that if you simply re-write the site using PHP, you will find many ways of streamlining as well as adding speed to the functions.
Sorry that this wasn't helpful, but you would be better off in the long run if you re-wrote it.
Check Sourceforge.net - they may have something...