There are a variety of labs and other institutes that offer classes in microscopy. Here's a small list of places to check into for training.
Shoals Marine Laboratory. The Shoals Marine Laboratory offers summer marine courses and research opportunities.
Friday Harbor Laboratories Friday Harbor Laboratories (FHL), part of the University of Washington, offers coursework for undergraduates, post-baccalaureates and graduate students. Spring and autumn sessions run a full academic quarter (10-11 weeks) with courses and research apprenticeships targeted to undergraduates and post-baccalaureates. In summer FHL offers six graduate-level courses plus one undergraduate-level course. Summer courses run 5 weeks in one of two summer sessions.
Oregon Institute of Marine Biology: OIMB offers a variety of courses during the spring, summer and fall terms. In the summer there are eight week term, several two week and weekend workshops available. Courses are open to qualified students from all institutions as well as those interested in continuing education. Courses meet for at least seven hours a day and are designed for upper-division biology majors, environmental studies/science majors, and graduate students in these disciplines.
Bamfield Marine Station: Bamfield Marine Station offers field courses in coastal and marine sciences. These University credit courses are open to senior undergraduates, graduates and, other qualified persons. BMSC courses are directly credited towards member university degree programs (UVic, UBC, SFU, UAlberta, UCalgary).
Smithsonian Tropical Research Institute: Field courses are part of STRI´s scientific training program and are mostly intended for graduate students. STRI also provides logistical and content support for tropical field programs in Panama run by North American universities such as the University of Pennsylvania, McGill University, Princeton University, School of International Training, University of California–Davis, Florida International University and Michigan State University.