The Economist has a reasonably good survey of the state of fresh water supply in the world. Most of the articles are not available for free online, but the paper copy of the Economist has them all.
Not surprisingly, most of the ideas on how to solve the current problems are centred around management and water pricing, these are not bad ideas, but should be combined with new methods. The general gist of the articles is that there is enough water it just needs to be managed properly.