I am so excited to see a corgi thread! I have a 10.5 year old Pembroke Welsh Corgi (Abby) and we just got a Cardigan Welsh Corgi pup (Winifred) about 5 weeks ago. Corgis are a fabulous breed with loads of personality and they actually smile when their tongues hang out of their mouths. Needless to say, I am a corgi lover. Our first two corgis came from a breeder in TX that my aunt was doing business with at the time so that's where Abby came from. When we decided to get another puppy, I used the Cardigan Welsh Corgi Club of America website
http://www.cardigancorgis.com/BreederDirectory.asp and the Pembroke Corgi Club of the Potomac
http://www.pwccp.org/Default.aspx to find registered breeders in my area. I started by checking out websites for those that had one and then sent emails to all of the breeders in NJ, NY, and PA telling them a little bit about myself, what I was looking for, and requesting more information. A responsible breeder will want to know more about you than you might think! The cardi breeder website actually has a column on the list of registered breeders where some breeders list their next upcoming litter. The breeders I talked to were primarily showing their dogs and had no more than 1 litter a year from which they chose their future show dogs and sold the rest as companion dogs.
I contacted a cardi breeder that had a litter of puppies born 12/22 and inquired if any of them were still available. She wrote me back and said she was waiting to evaluate the pups at 8 weeks of age to determine which had show potential and which would be better suited as pets. She sent me a Puppy Questionaire to fill out in the meantime. Most breeders are happy to refer you to another reputable breeder if they do not have a puppy suited to your needs. Luckily, one of the puppies in the litter came available when another prospective owner backed out and she wound up being a great match for us. She was described by the breeder as "the largest female with a very laid back disposition" and she has lived up to that 100%. Winnie has been the dream puppy. Her house training is going really well, she's not nippy, rarely barks, and is equal parts "Let's play!" and "Let's snuggle!" While cardigans are thought to be a bit more laid back than pembrokes, there were 2 pups in her litter that were more high-energy and very yappy that the breeder would not have let go to an apartment home or less active owner.
I mention that b/c some people have mentioned barking, nipping, and food agression as corgi tendencies but I think that depends moreso on the individual dog. All of our corgis have been extremely food-motivated but that only presented itself in positive ways b/c it made them so easy to train. We had Abby's brother (Jack) from the same litter before we got her (she lived with my aunt in TX amongst a herd of corgis for her first 5 years). He was a typical herding dog type that had lots of energy and was on the noisier side, but he was amazing at agility and an awesome companion. He had to be put down at age 5 b/c he developed a terrible brain tumor, but was always a great dog. We got Abby after the loss of Jack b/c we weren't ready for another puppy and my aunt thought she'd enjoy being an only dog. She's from the same litter, but is the polar opposite. She is mellow, snuggly, and almost cat-like. So not all corgis are food crazed maniacs although I was always happy our first corgi didn't have the legs of a lab or he might have been a counter surfer

.
The AKC question has been pretty thoroughly answered, but in my case Winnie came with a "Limited Registration" which means that she can compete in any AKC event except conformation. Her breeder offers a $100 rebate if she wins an AKC title (Rally, Agility, Obediance, Herding) which is nice. We did not have to sign a spay/neuter contract, but even if we were to breed her, her puppies could not be AKC registered due to her Limited Registration. We're spaying her regardless, but I thought I'd put that out there.
Sorry for the novel, but I adore corgis and wanted to add my .02! Also, petfinder.com is an awesome tool for finding adult dogs, but the purebred corgis that do pop up are usually adopted really fast (like within 24 hrs) if they don't have any major issues so you have to be ready to act fast. And lastly, if you decide you don't want the trouble of raising a puppy but want a purebred corgi, many breeders have adult dogs (although I've seen as young as 6 months) that didn't pan out as show prospects, but would still make fabulous pets. Many of them are already housebroken, know basic obediance, and some are even started in agility! Let me know if you have any questions and Good Luck!