Clean Up Australia - Marine Debris
http://www.cleanup.org.au/au/search.html?kw=marine+debris

A great initiative of the Clean Up Australia campaign. Lots of information and links.

Global Marine Litter Information Gateway
http://marine-litter.gpa.unep.org/

A fantastic UN site about marine litter and debris, including loads of pictures. Includes kid''''s stuff and global and local action.

Marine debris in Canada
http://www.ec.gc.ca/marine/debris/homeeng.htm

An excellent site with a lot of information and resources which is relevant to any coast or ocean not just those around Canada. Has photographs which can be downloaded, simple games, activities (mostly involving personal action), some further useful links and more.