short answer...yesYes you can. However, you must temper the chocolate first. You'll need a double boiler (or a good fitting bowl and pot) and a very good thermometer. You can use the old fashioned candy thermometers, but I prefer the digital kind.
Once the chocolate is properly tempered you can place it in the molds, and once it is chilled they should pop right out. If the chocolate is not properly tempered, the chocolate will stick to the molds, break, or come out looking dusty white on the surface.
Tempering may sound burdensome, but really, its not that bad. I don't have my notes in front of me, but you can probably find the correct tempering procedures on this site or on the internet. Please note that dark chocolate requires different temperatures than milk chocolate. Other than that you are set to go! Good luck :chef: