NOAA provides a well-conceived platform for students to research, gather, and analyze ocean current data. Extension activities also provided.
This site explores the correlation between the pattern of ocean currents and the air circulation above them. There are lessons for the low, intermediate and advanced learner. This one is for the intermediate group.
http://www.windows.ucar.edu/tour/link=/earth/Water/ocean_currents.html
This is a lesson plan to teach students to map ocean currents and teach the effect the correlation of wind, water, land masses, etc. has on current In lieu of assessment questions students summarize their observations and label the map.
http://www.teachervision.fen.com/childrens-science-activities/lesson-plan/2916.html
Describes eddies, how they form and gives a brief overview of Hawaiian eddies
http://www.geol.sc.edu/cbnelson/eddy/eddy.htm