Mobissimo

If you're a beer aficionado and want to head for the best beer spots wherever you travel, RateBeer should definitely be one of the websites you should consult before leaving. 

RateBeer was founded in May 2000 by Bill Buchanan as a forum for beer lovers to come together and share their opinions of beer and breweries. Established and maintained by dedicated volunteers, RateBeer has become the premier resource for consumer-driven beer ratings, features on beer culture and industry events, weekly beer-related editorials, and an internationally recognized, semi-annual RateBeer Best competition. The community now has thousands of members from more than 60 countries who have rated tens of thousands of beers from around the world. Our mission is to provide independent, unbiased, consumer-driven information about beer and breweries and to enhance the image and worldwide appreciation of beer.

We tested the site out for San Francisco, and though it returned some of the establishments that have been around for a while, it missed the new locations like Southern Pacific and smaller bars with good beer selections like Shotwells. But it's definitely a good website to add to the ones you already currently use to research your trips.