You could also try inserting the stick before freezing the chocolate filling and then dipping them in chocolate. Then you can poke the stick into a piece of styrofoam to hold it upright while it drys, similar to cake pops. This would make them more round but a little more tricky to work with. My little kids don't care if their chocolate lollipop has a flat bottom or not, so I just went the easy route of inserting the stick after they had already been coated in chocolate and hardened.
Wrap in cellophane or plastic wrap, and tie with a pretty twist tie or ribbon, and you will have a beautiful stocking stuffer, Valentines treat, party favor, or small sweet gift for any other occasion.