Woods Hole Oceanographic Institution
Whoi: What Causes Tides?
The Woods Hole Oceanographic Institute provides an in-depth but easy to read article on the role of the moon and the sun in respect to tides.
PBS
Pbs Learning Media: More on Galileo's Big Mistake
Even great scientists make mistakes! This illustrated essay from the NOVA Web site looks at Galileo's theory of the tides, which, while well thought out, was wrong.
Ducksters
Ducksters: Earth Science for Kids: Ocean Tides
Did you know the rising and falling of the sea level is caused by the gravity of the Moon and the Sun? Kids learn about ocean tides including tidal currents and types of tides on this site.
MadSci Network
Mad Scientist: Why High Tide Away From the Moon or Sun?
An excellent and thorough answer to the often asked question about high tide "bulges" on the side of Earth facing away from the Moon or Sun.