The Cell Cycle & Mitosis Tutorial, The Biology Project
http://www.biology.arizona.edu/cell_bio/tutorials/cell_cycle/main.html

Meiosis Tutorial, The Biology Project
http://www.biology.arizona.edu/cell_bio/tutorials/meiosis/main.html

Meiosis and Mendelian Genetics, a tutorial of the chromosome theory of inheritance:
http://mentor.lscf.ucsb.edu/mcdb4a/meiosis.htm

National Hemophila Foundation:
http://www.infonhf.org/