Cream of coconut is a coconut flavored sweet syrup sold in cans. It is basically a form of coconut cream to which corn syrup or sugar is added. Coconut cream is a liquid extracted from coconut pulp. This is opposed to coconut milk which is just the liquid that sloshes around inside of a coconut.
The genesis for cream of coconut was in making it easier to produce and use sweetened coconut cream in beverage and food products. Squeezing or extracting coconut cream from coconuts each time you want to make a drink is laborious and slow.
Don Ramon Lopez Irizarry found a way to make this process easier and more efficient and in so doing developed the first cream of coconut called Coco Lopez in Puerto Rico. Soon after in 1954 the Pina Colada was born using cream of coconut along with rum and pineapple.
Coco Lopez today is the leading brand of cream of coconut. I use it myself and it's a good product. They use real sugar and not high fructose corn syrup. Some other brands are not as good.
Cream of coconut substitutes
Sometimes you don't have a can of Coco Lopez in your cupboard but you are dying for a pina colada. Here are some cream of coconut substitutes:
Coconut extract and sweetened condense milk (if you don't have any extract use coconut rum in place of normal rum in the drink recipe)
Canned coconut milk (normal not low fat). Take the top one cup from an unshaken can (the coconut fat rises to the top), add 1/2 cup half and half or cream and superfine sugar or simple syrup to taste
Let us know how these turn out.