The Franklin Institute
Franklin Institute and Science Museum: Seeing
Take a look at this sight and all of the activities it has to offer. Has great activities to use in the classroom as well as world wide web links.
Khan Academy
Khan Academy: Prokaryote Interactions & Ecology
Learn about cooperation and "multicellularity" in prokaryotes including mutualisms, commensalisms, parasitisms. Also find out the role of prokaryotes in the carbon and nitrogen cycles.