It kind of depends on what you want to do but I always just check the yellow pages. Some people go for the super-friendly vets while some call around for the lowest prices.
I usually sacrifice personal attention and pick larger multi-vet clinics that have scheduled appointments during the day with overnight emergency walk-ins. These places are usually fully-equipped. But that also means my pet rarely gets the same vet and I have to stay on top of things with clear answers to their questions on each visit. If possible, I usually prefer a university's vet clinic which is staffed by vet students and instructors. Again, the downside is that large clinics or teaching clinics won't take time to answer lots of personal questions. That's why I use the internet.
Anyway, just figure out what's important to you -- personal attention, low cost, well-equipped -- and then selectively seek that out.