Microorganisms: http://www.neok12.com/Microorganisms.htm

Plant cells: http://studyjams.scholastic.com/studyjams/jams/science/plants/plant-cells.htm

Animal cells: http://studyjams.scholastic.com/studyjams/jams/science/animals/animal-cells.htm

Cell Extravaganza: http://www.cellsalive.com/