Beer Mapping has come up a couple of times and I really like it as it’s easy to pinpoint things with their Google Maps mashup. http://beermapping.com/city-beer-maps/
I don’t have as much faith in Beerfly reviews on BeerAdvocate. I’ve seen places I really enjoyed dissed pretty hard but it is useful for putting a list together for further research. You also have to be registered to use its fancier features. But here’s a tip: Enter this into Google to get a quick list:
city name beerfly site:beeradvocate.com
Fancy a Pint is a great UK based site. It’s London centric, though. I used this on my last trip and found a great local pub that I would have otherwise missed.
Beer in the Evening is another English site. It has broader coverage than Fancy a Pint. It also has a pub crawl generator, which is fun to play around with. http://www.beerintheevening.com/
Beer for breakfast is a fun thing during vacation but otherwise it seem very close to alcoholism to me. On occasions I have sampled beer in the morning b/c I remembered that I wanted to take a gravity reading. I always get very odd looks from the wife when I drink the sample. But that is not really beer for breakfast for me