We have enough problems on our own turf that we should not be meddling in China's currency affairs. Forget the fact that we owe that country tons of money. How can anyone take our monetary policies seriously when we are trillions of dollars in debt? It makes no sense to get even more wound up in other country's problems.
By manipulating currency value, China is supporting companies that export products. As a country that has embraced capitalism, it will not take too long for them to realize that the government cannot guarantee a companies profitability. China will bankrupt itself by effectively subsidizing too many of its' manufacturers. Coupled with growing domestic demand for products, China will have to let its' currency rate become market driven.
The US owes a large amount of money to China and depends on China for many of its goods. While China is also dependent on the US in many ways, I don't think that China will hesitate to punish the US for such interference, even if it brings some hardship to the Chinese people.
Any meddling on the part of the United States in Chinese currency will end in disaster. Consumers already depend upon cheap Chinese goods. A free market system will eventually take care of itself--when Chinese labor is no longer cheap, goods will cost as much as American-made products. The same will happen in emerging markets such as Brazil, India, Thailand and others. When wages increase, prices become more competitive. There is no need to control Chinese currency. When wages go up, products become more expensive to make and the Chinese economy will take care of itself in a decade.