You can find the Yelp Business ID in the URL for the listing. The ID appears after www.yelp.com/biz/ in the address bar, and is generally composed of the name and location of the Practice separated by dashes. For example, the ID in the following URL is "dentistry-for-kids-and-adults-canyon-country":  www.yelp.com/biz/dentistry-for-kids-and-adults-canyon-country.