University of Arizona
University of Arizona: Genetic Drift Simulation
This site from the University of Arizona runs a two-step simulation of Genetic Drift. There are teacher's notes included. A great site to aid in understanding Genetic Drift.
Palomar Community College District
Palomar College: Practice Quiz for Gene Flow
This site from Palomar College contains an interactive practice quiz containing four questions on major concepts regarding gene flow. A great learning tool.
University of California
University of California Museum of Paleontology: Evolution 101: Gene Flow
An explanation of the process of gene flow and how it can cause genetic variation within a population.