Lunar Hydrogen Revisited:

Okay, I’ll have to eat a little crow here. Hydrogen is not as scarce on the lunar surface as I had previously believed. I was using information from some Apollo era books in our library on the composition of the local geology. However, the recent Lunar Prospector mission has revealed the presence of significantly better deposits of hydrogen in the “cold traps” of the lunar poles, areas of perpetual shade generated by crater walls where temperatures are cold enough for the hydrogen to condense.

Lunar prospector used the scattering of epithermal neutrons, and their absorption by hydrogen deposits in the soil, to detect the hydrogen deposits. If the conclusions of the following report are accurate, there could be on the order of 10^8 metric tons of hydrogen on either pole of the moon. This much hydrogen could easily support lunar bases. It could also support a few thousand nuclear thermal space missions using nuclear derived hydrogen fuel before being completely expended. This offers far better prospects for initial settlement of the moon and its use as a fuel base for missions farther out into the solar system.

Lunar Prospector Hydrogen Report

It was also mentioned somewhere else in some of my more speculative reading that cold traps may be constructed for industrial purposes, and that this could attract hydrogen from the solar wind to pool in the shade (though how slowly, I am unsure).

An additional resource: The map of neutron scattering.

NASA Data Maps