This animation demonstrates the changing declination of the sun with a time-lapse animation. It shows how the shadow of a building changes over the course of a year as the declination of the sun changes.

An interactive simulation of Earth's seasonal dynamics that includes the axial tilt and other aspects of Earth's annual cycle.

This is part of a larger lab from the University of Nebraska at Lincoln:

An interactive that illustrates the relationships between the axial tilt of the Earth, latitude, and temperature. Several data sets (including temperature, Sun-Earth distance, daylight hours) can be generated.