The best site is http://dogoftheday.com/

Here are a few of others I have gone to, there are many more

2000 DOG NAMES Naming your puppy

AKC - American Kennel Club for Purebred Dogs

Cool Dog Supplies at SitStay.com

Crazy for Dogs

Dog Breed Information Center: All Dog Breeds

Guide Dogs for the Blind

Leader Dogs for the Blind

Ray Gegner's Custom Dog Leashes

Southeastern Guide Dogs, Inc.

The Dog Hause Fonts

The Dog Hause Quotes 1-12

VetInfo - Veterinary Medical Information for Dogs and Cats

WorkingDogWeb 9 Guides to Active & Working Dogs, Breeds, Training, Sports, Health, More