OOOH i make my own.
Put the milk in a pan, bring it slowly up to heat stirring all the time (you want it just hotter then what your finger can stand, but you don't want to boil the milk)
In a double boiler (a bowl over slightly simmering water) place the chocolate in the bowl and let it melt down slowly.
Once the chocolate has melted take a small amount of the milk and a wisk, pour a small amount (about two table spoons worth) into the chocolate and using the wisk stir into the chocolate, the chocolate will start to seize up, however keep mixing, once incorporated add more milk and stir in, after 4 - 6 additions you can start adding about a 4th of a cups worth at a time beating with the whisk
Eventually it will start to become smooth and milk, add all the milk, give it another beating, stick it in the fridge and let it cool back down.
You'll get fats/milk solids/chocolate forming on the top of the mixture just use a spoon to remove it or, I use a gravy/oil separator
you can add sugar if you want, you can also add a cinnamon stick and let it sit in the mixture while it cools, I've added a touch of salt too, changes its taste and worth a try (use good salt not table), you can add chilli and other spices too..
It makes a really nice chocolate milk and its a lot healthier and you can use your own favorite chocolate