Forget that tired old image of the moon as a entirely dry locale, devoid of any moisture. A recent set of discoveries have found that not only is there water on Earth's sole satellite — but the water is everywhere.
Three papers appearing in the upcoming issue of Science Express outline the discovery of pervasive water found clinging to the surface of the moon. Infrared spectroscope measurements from three different space probes have detected absorptions that indicate the presence of water or hydroxyl (which is, itself, a strong indicator for the presence of water) on the the lunar surface, with one model suggesting water makes up a few tenths of a percent by weight in the optical surface. This water is apparently clinging to the moon's surface, rather than being absorbed by dust.
It's hardly a vast lake, and it won't yet support that lunar agricultural colony you've been dreaming of, but it's far more water than scientists ever expected to find on the moon, and it could prove a valuable resource to future lunar visitors. The researchers have also found that the concentration of water is higher toward the poles, lending credence to the theory that larger deposits of water exist near the poles, and researchers note that it's possible we'll continue to find wetter lunar regions in the future.
So where did all this water come from? Although meteors or comets may have periodically brought water to the moon, the prevailing theory among the three papers is that solar winds have carried hydrogen to the moon's surface, where it has bonded with the oxygen in the moon's own dust and produced water.