From the New York Times: Simple syrup, indispensable to bartenders, is usually nothing more than equal parts sugar and water, heated until the sugar dissolves.
Depaz, a plantation on the Caribbean island of Martinique that makes fine rum from cane juice, has introduced a syrup made of freshly pressed sugar cane juice diluted with filtered water, something you cannot make at home. It is an amber color, like the rum, and it has a clean, slightly honeyed flavor. You can use it to sweeten iced tea, and in baking, too.
Depaz Cane Syrup, in 23.67-ounce bottles, is $10.99 from igourmet.com.
...I wonder if you can get this on-island?