Maryland Sea Grant's Education site with good information on Chesapeake Bay biofilms:
http://www.mdsg.umd.edu/Education/biofilm/index.htm

Mega-list of biofilm-related sites:
http://www.erc.montana.edu/~ernie_v/biofilm_sites.html

Pictures of medical, environmental, and industrial biofilms, curriculum, and other links:
http://www.asmusa.org/edusrc/edu34.htm