These ice cream cone costumes were made through instructions on FamilyFun, a great crafting magazine.
You use stuffed womens/girls stockings for the swirl of the ice cream. Glued to the bottom of that was a circle of foam as a belt, which I duct taped together and made suspenders to hold it up. The ice cream was glued to the top and vinyl (from fabric store) cone was glued to the bottom of the foam belt. Lots of hot glue! The sprinkles are drinking straws cut up and glued on.
For the top I used baseball caps (I had to sew ribbons on for stability because they were a bit top heavy). I hot glued more stockings and a Styrofoam ball, painted red with a pipe cleaner stem as the cherry on top.
These homemade ice cream costumes were a HUGE hit!