How do you make flower molds out of frosting?

Many floral designs can be hand-crafted by using a variety of plastic or metal tips in a pastry bag. (See associated link below)

Many types and sizes of plastic molds can be purchased from craft stores, but the recipe for the icing will vary, according to whether you want it colored and/or flavored.

Below is another link to a great site that may help you with the icing of cakes.