Note: a BA hat tip to Larry Klaes for the heads-up on this one.
This is way cool: Ralph B. Roncoli of the Solar System Dynamics group at JPL has put together a document called Lunar Constants and Models Document. Sound boring? It's anything but. Sure it's loaded with numbers and tables and data only a major geek like me could love (did you know that "the latest lunar gravity field, LP150Q, is a 150th spherical harmonic degree and order model"? Me neither).
But it also has some very cool descriptions of our nearest cosmic neighbor. It talks about how the Moon's orbit is changing (due to the influence of the Sun's gravity), how lunar eclipses work, and how future astronauts can tell time on the Moon's surface.
It also has fantastic images of the Moon. It has a relief and surface marking map of the nearside (here's a taste, and you can even order a copy). My favorite, though is the link to this clickable, zoomable google-like map of the Moon.
You know, we're going back to the Moon sometime pretty soon. This is a pretty handy thing to help pave the way.