Hops are the major flavoring in beer and give it its bitter taste. Last year there was a fairly drastic hops shortage with high costs implications for craft and small brewers. This year there is apparently a glut of hops but this is unlikely to cause beer prices to drop.
Stan Hieronymus, at Appellation Beer has been posting about hops production in California in 1900 which is very interesting historical material.
Farmers harvest hops in the fall and usually brewers use dried pellets to flavor their beer. Some brewers use the fresh green cones to brew beer, right after it is harvested. You need a larger amount of fresh hops to make a decently flavored beer. Several craft brewers, including Sierra Nevada and Rogue Ales, produce fresh hops beer. Several bars in New York, including Blind Tiger, have been serving these beers this fall.