Look for breeder referrals from the AKC or UKC websites. But then you need to start asking the breeder questions like what kind of health testing they do (for these breeds, luxating patella/elbow tests are importnat), how their dogs are socialized, where the parents live. And then you'll probably want to visit the breeder yourself to make sure these are the dogs you want to get from
(some of the questions here are breed specific)
http://www.veterinarypartner.com/Content.plx?P=A&A=302
http://www.barkbytes.com/b4ubuy/qtaskb.htm
http://www.cluebus.com/holly/breeder.html