Rules vary by country, but currently in the US, a product with 95% organic ingredients qualifies as organic. Since hops are a minor component compared to malt and water, a brewer can use all conventionally-grown hops and still be able to call the beer organic. Most organic hops come from New Zealand, which doesn't have the diseases that causes hop growers to apply chemicals. But there are only a few NZ varieties AFAIK, so this severely limits the brewer. Some organic beers in the US: Wolaver's (I believe brown, IPA, pale ale, and also a hard cider), Golden Promise (Scotland), Sam Smith (England), Pinkus (Germany), Butte Creek (Chico, CA), Foret (Belgium), Jade (France). There is also an organic brewpub recently opened, I believe in CA, the first of its kind. Whole Foods Market (full disclosure: this is where I work) has a couple of organic beers called Lamar Street.