"Once it's all at LEO what do we do with it? Tank-up Moon-trucks?"

If there isn't minable water at lunar poles, it's likely that other destinations such as Mars or asteriods would be more attactive, and if there is minable lunar water, then it's likely that evenally this lunar water would be shipped to LEO instead of from Earth- it takes far less energy to get from the Moon to LEO than from Earth to LEO, but our costs of rocket fuel on the Moon would first need to become cheaper.

There is thought to be more 10 billion tons of water on the Moon, but even if this is correct this doesn't say how much water is minable [there is billions of tonnes of gold in our oceans and none of it is minable]. If there was say 1 billion tonnes [1 trillion liters] which was minable, and each liter of this mined water had an average value of $10 per liter, that's a gross value of 10 trillion. If during the first few years lunar development the average price of water was $1000 per liter, and the average price of electrical power was $25 kw/hr. A business which makes rocket fuel would need to pay $125 for the power needed and $1000 per liter of the water needed, obviously in this situation rocket fuel would need to have a higher price than $1125 per kg, so say it's $1500 per kg. If water is at the same time as this being sold in LEO at $2000 per liter [which is probably about as high as it could reasonably be and would probably be closer to $1000 per kg] this doesn't make shipping water or rocket fuel from the Moon to LEO very likely. But even if water in LEO is less than $1000 per kg and say rocket fuel was as low as $1000 per kg, if you are mining water on the moon and water is being sold at $1000 per kg and rocket fuel is being sold at pricey $2000 per kg, you can't make a profit shipping water or rocket fuel to the lunar surface from LEO. BUT in this particular situation both the LEO operations and the Lunar operations could be competive if the shipping destination is Earth/Moon L-points or GEO, because in terms energy costs of shipping [the delta-v required] these destinations are roughly equal [it' at the halfway point] from LEO or Lunar surface. Or in other words, if rocket fuel is being sold at LEO and Lunar surface for less than $2000 per kg, then it could be reasonable that rocket fuel could sold at $3000 or more at L-points or GEO.

So at the moment without there being any lunar mining or gas stations in LEO, the cheapest way to get relatively small qualities of rocket fuel [say less than 100 tons] to LEO, GEO, L-points, or the Moon, is shipping it from Earth directly to these locations, but if there is a longer term need of more than 100 tons, a source of water beyond Earth starts to become an alternative way of getting cheaper rocket fuel to these destinations. At the moment the lunar surface is the most expensive location to ship rocket fuel from Earth. At the moment, it costs you $2000 per kw/hr for power if you want to buy it at ISS, if you wanted to buy water at ISS, the govt could charge you any amount money- as a "guest" they could give it to you in small quantities [one or two liters], if you wanted a ton or more they would probably have consider charging you for it, and number they might pull from their ass, might be say $20,000 per kg, which would be just another way for them to say, you should get this ton of water you want from somewhere else. And they could rightly claim they not in the business of shipping water.

We need a market for water in Space, we need a business that ships water into space. There is trillion, trillions, and trillions of tons of water other than on Earth in Space environment of this solar system.
Water plus electrical energy gives a chemical rocket fuel. If water is shipped into Space, there could be a market for electrical energy in Space.
The cheapest way of getting a market for Electrical energy, chemical energy [rocket fuel], and water in space is for the govt or even a NGO, is to spend money to have water shipped into space, and then to *give* this water [which is essentially the same as giving money] to any party which will convert the water into rocket fuel. They get paid only when they can use this rocket fuel for something valuable or sell it to another party which considers the rocket fuel as valuable. Govt cost: about 1/2 billion dollars.

The next cheapest way of the govt getting a market for electrical energy, chemical energy [rocket fuel], and water in space, is to explore the Moon to determine whether or not [and to what extent] there is minable water. Govt cost: about 5 billion.

A another thing the govt could do is encourage the development of the technology of transfering electrical power. And they are currently doing this using a small prize system: http://www.nasa.gov/home/hqnews/2005/mar/HQ_m05083_Centennial_prizes.html
This is projected to cost .4 million but it *could* be the beginning of bigger goals and this *might* evolve in a total program cost of somewhere below 1 billion dollars