Have a look here:
Valentine Bulletin Boards:
Class in a Box
Cut out a large heart out of paper. Decorate the heart to resemble a valentine box of candy. Have each child create a small picture of themselves. Glue each of your children's pictures in the heart (lined up like the candy) and write their name below their picture. You can title this board "One Sweet Box," "Class in a Box," "My Sweeties," "Our Assorted Sweeties," etc.
Give your children heart shaped sponges to paint with. Let them all create on one big piece of paper (one that will fit on the board) Next, ask the children who they love and write this randomly on the bulletin board
Simple, yet functional, Valentine Holders inspired by Ms...
Valentine Bears and Hearts.doc