how do i do the effect of hearts or stars on wires that i see on so many cakes stuck in the centre of the cake

1st you need to cover the wire w/floral tape or dip them in chocolate.
Cut your stars/hearts and either sandwich the wire between 2 or cut them thicker and thread them onto the wire. If the latter, dip the wire into gumglue & shake off, then thread on the decoration. Allow to dry before placing.
When ready to put on the cake again, make sure the wire is covered as above. Never stick plain/uncovered wire into a cake. It is best to put something into the cake - like a flower pick or straw and put the wires into that. It helps keep the wires from coming in contact w/the cake and gives stability so the wires don't cut thru the cake & flop around

Duplicate post:
http://cakecentral.com/cake-decorating-ftopict-735664.html