"An orbiting "gas station" is an important requirement for the long-term future of human interplanetary exploration, a study by NASA engineers suggests.
...
NASA appears to backing away from developing in-space fuelling stations itself, but has set up a $5-million prize fund for any company that can create one.
...
The $5 million will go to the first team to build, launch and test a model of a liquid hydrogen and liquid oxygen storage or production depot in Earth orbit. According to the draft rules, the tanks must be launched into low-Earth orbit and hold at least 20 kilograms of liquid hydrogen and 120 kilograms of liquid oxygen for 120 days. The deadline is 2012."
http://www.newscientistspace.com/article/dn9259-orbiting-gas-stations-key-to-interplanetary-exploration.html
[linked from http://www.transterrestrial.com/]

Not a bad idea. 5 million seems bit low, but if you keep total payload to around 500 kg- that's $10,000 per kg.
I like my idea better: pay for water payload launches- then give water to those who could use it.
But this plan is cheaper and is a step in that direction.
Spacedev should do this- basically break even on it, but gain from the PR from it and this lines up with long range goal of asteriod mining.