I know exactly what you mean~I have got a serious sweet tooth. I don't know what kind of diet you're on so I don't know what you have to limit (carbs? fat?) so be sure to read the nutrition lables. I'm on South Beach and they allow 100 calories of these per day: sugar-free jello; sugar free dark chocolate (also tried the 90% cocoa); sugar-free fudgesicles; sugar-free hard candy (you get the fewest calories and carb grams with most of these).
I also use diet sodas to quench that craving. If you're not into artificial sweeteners then I'd stick to the low sugar dark chocolates.
Good luck with managing those cravings on your diet!