Here is a link to a Royal Society (Great Britain's Scientific society of note) article that might be worth a read:

http://royalsociety.org/document.asp?tip=1&id=7366

The statistics on the new installations of wind turbines throughout the world can be seen at this site:

http://www.gwec.net and more specifically:

In case you haven't seen it, Paul Gipe has another article (and a great presentation link in this article) on his website.

Most people really do not have the vaguest idea of the wind resource across the U.S. So it should come as little surprise that they always fall for lines such as "wind could do 10% of the US supply by 2020", or maybe 6%, or maybe 2% if you use some of the Energy Information Agency projections. Of course, the answer to "What is the U.S. wind capacity?" is slightly tricky, and it has less to do with the wind resource than most people might suspect.