We're past the winter solstice (finally!) and, at least in the Northern Hemisphere, getting a bit more sunlight every day. It's hard to see a difference yet—in Washington, D.C., the days are lengthening by only about half a minute per day this week. (You can chart your local sunrise and sunset times here.) So it helps to look at the big picture.
For a refresher on how the Earth's tilt and position determine the seasons, Prentice Hall has a decent animation. The Astronomy Department at the University of Illinois has a slightly more sophisticated one that includes a view of the Sun from our perspective.
It's hard to break out of the pre-Copernican worldview that the Earth is stable and the Sun is moving. Two animations from the University of Nebraska work with that misguided intuition as they animate the change in strength and position of sunlight over the seasons. But sometimes animations just can't compete with real life. Nebraska also has a time-lapse video that reminds us just how dark our days are right now, and how light they will become.